Did you open up a vanilla map along with a GIM map? If you did, you probably loaded up GIM's global, IE its configuration data. So if you go to the vanilla map in the editor tab and then open up configuration data, you're not looking at vanilla data but GIM data.
Either that or you accidentally saved GIM's global data. Vanilla maps don't have global data saved, there's only 6 map files associated with them. So if you had GIM campaign maps and then wanted to get rid of them, you can't just overwrite them with the vanilla map files, you need to also delete the global data files associated with them.
Also, in regards to having multiple maps open in the editor at once. Because the vanilla maps don't have global data, you won't get that prompt to load the map's global data when you load it, and it will instead retain any current global data opened up in the editor. So if you open up a GIM map first, even if you close it before opening up a vanilla map, it'll still have GIM's global data when you look up configuration data. Need to close / reopen the editor or have two separate editors open if you want to actively compare values.
Honestly when I played GIM the other day to try 1.51, I disregarded the instructions (it asks you to delete your entire map folder which is just AFoanfuAOFH unnecessary). Instead, just need to put DKII.exe, DKII.icd, DKII-DX.exe, patch.dll, QMixer.dll, SFMAN32.dll files into the main directory. Then run DKII.exe for 1.51 or DKII-DX.exe for 1.7. For GOG installations anyway.
Of course, now I might suggest deleting your map sub folder to get rid of GIM stuff and replace it with a vanilla copy instead. And, you might also want
this.