I have opened my current project's esp in MW Enchanted Editor to clean it from those GMST before playing. Now, I saw that a whole lot of other cells far away from Solstheim, where I changed cells, suddenly got marked as changed (namely Bitter Coast, Westgash and unspecified ones(wtf?)). I have never ever touched those cells while building, so I'm a bit confused now Anybody has an idea, why that happened? Also, would it be safe to delete the entries of those cells with MWEE?

I assume this is a known issue, but I did not find anything specific about it in a quick search of the old forum. Today I decided to combine three mods.
Opened the CS ( latest version 1.6.0.1820)
Selected the three mods, made one active, went out for breakfast, came back and the mods had all loaded nicely.
File Combine Give the combined mods a new name.
CS whizzes and bangs for a few seconds and the new Mod is now the Active mod and the other mods are removed from the loaded list.
Files -> datafiles -> details to check against my checksheet. All the additions and changes and deletions are there and so are 19 EXTERIOR CELLS that were not touched in any of the mods.
Just shoved into the new mod by the Editor for the halibut?
( the original 3 mods changed exactly one interior cell in their original form).
So I open TesTool and tell it to clean this new mod ( all three of the progenitor esps were cleaned before the combine) TesTool rips out the 19 cells since they are all EMPTY cells and cleans the ambi value in the interior cell.
6 wilderness, 3 west gash 10 bitter coast cells. Just a warning and maybe old news to some, It appears to be a harmless snafu hidden somewhere in the editor code....until someone puts a mod into some of those cells.

I've had this happen, but not like you have. Mine usually occured when I "mass" moved a bunch of objects and accidently picked up stuff from adjoining cells.

I use TESAME, but I suppose the same will hold true with whatever you're using: Make a back-up of the original then remove the cells and see what happens. If it looks like everything is ok, proceed. If not, go back to your back-up.

Only other thing might be that you have changed a particular object that would be common to those cells... Tree maybe, or something else???

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I noticed like 11 to 13 cells from Bitter coast and west gash regions that I did not change.
They showed up in the details part of the CS.
I did not check to see if they were marked * for a change in the Cell view window.
I deleted them and they Have not come back yet.
I noticed it like 3 weeks ago but I did not see any posts so I figured I would wait to see if anyone else had the problem.
I also have not been able to make it happen again.
I am making a Morrowind only plug in. I have both expansions.

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I sometimes get a bunch of them when I merge plugins. The Details list shows the cells, but doesn't list any changes made for those cells.

I'm pretty sure it's always the same batch of cells: I kept track for a while, but stopped worrying about it a long time ago. (I don't have a list of the cells anymore.)

I figure it's just one of those weird glitches. It seems to be completely harmless, so I just clean the cells from the Details list (but only cells that don't have any changes listed).

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Now this is going to be interesting. For reference I took a screenshot of what MWEE lists. I compared the coordinates from MWEE and CS (see Region Paint). The unnamed cells from that list are those Wilderness cells you see South and West of Solstheim, plus the one far West to the Bitter coast. The others all are on the West coast of the Mainland, on the water-land-frontier.

As I'm writing this I just notice, that this data doesn't matter at all, hehe. It may give a hint on glitch-mechanics though. Dinkum's mentioning of merging got me thinking. I forgot I proceeded on a modular way to build my current project and merged the modules (restarted several times building, so I forgot, what I did at the beginning:)) However, I loaded another plugin into MWEE (Rhedd's Heads merged to one file, which I never bothered to check for dirt) and lo! references to cells, and unsurprisingly they were the same as in my current plugin (minus the BM-added Wilderness-cells). So I assume, it is indeed safe to remove those entries. Guess, it's not only always a new functionability of the CS you learn by progressing with modding, but a new bug too.

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I just re-merged a couple of plugins I had merged recently and remembered as having those extra cells in the merged .esp (which I promptly cleaned), and I got the usualy suspects.

Comparing to your screenshot:

I don't have the two Hirstaang Forest cells or the Elin's House cell, but the other nineteen cells are an exact match to what I have.

As I said, from memory I'm pretty sure those ninteteen cells are the same ones I always get.

When I clean extra cell listings, I'm always careful to only clean ones that only list the cell name itself, without listing any actual changed data. (When I unexpectedly see a cell listed with changes that I don't remember making, I investigate before cleaning the cell from the .esp file.)

As long as you're careful to only clean cells that don't list any actual changes, it should be safe.

Edit:

For reference, I'll go ahead and put the list of cells here.

(-12,3)
(-12,2)
(-12,1)
(-13,4)
(-13,3)
(-13,2)
(-13,1)
(-14,5)
(-14,4)
(-14,2)
(-15,7)
(-15,-8)
(-16,8)
(-16,7)
(-19,15)
(-19,14)
(-20,15)
(-28,24)
(-29,23)

As far as I remember, that's the same list of cells I've always seen when this happens after I merge .esp files.

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As I've seen, all those cells are without any further data, except the Forest and Elin's House cells, which are mine Based on your experiences, I feel even more safe to remove those entries now. Thanks very much for sharing
I have the feeling, there's lots of surprise waiting for us when examining mods on our HDs with this new knowledge.

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I always clean mods I download before they get anywhere near my game, and I know I've cleaned those nineteen cells from a few mods.

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TESTool will automatically remove the culprits.

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Merging plugins is what I was doing. It is easy to fix if it happens.
I may test a little later.
The plugin I noticed the problem with was merged with another plugin.
But I also use combine loaded plugins with only one plugin just to make a backup.
I do not think I get the extra cells unless I am merging 2 or more plugins.

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