The problem is indeed with the import, I would rather look at the document templates used during the import, are you sure that the 3 machines use the same asm and prt template?
I have a big penchant for the coyote answer because I encountered a problem with my parts files which, according to their basic configuration, changes the game in terms of imports.
Then there is also the fact of having or not done the function recognition (available in premium)
Fixed an issue by copying the path of the default templates to the location of the document templates files . And it is these "templates" that must be used so as not to weigh down the newly generated files. ("Default Templates" and "Always Use Default Document Templates"
Normally, we only use our own part templates, which seems to weigh down the files generated during the import considerably.
Now, the file size is acceptable, even if it differs very slightly on the 3 stations, it has nothing to do with it.