file name change during file exchange between translator and editor

Dear Studio experts,

I have had this issue for a while and wonder why this happened.

When I send a Studio file to this colleague for editing, the edited file would come back with a very minor change in the file name.  It took me a while to nail down the difference.  No wonder I always had trouble updating my file with her edited file in Studio!

For example, I sent her a file named xyz.docx.sdlxliff.  When she sent back the file, the name because xyz.docx sdlxliff (the dot is gone with a space between docx and sdlxliff). 

When I brought this to her attention, she was as puzzled as I was, cause she did not change the file name at all.

Does this have anything to do with the Studio versions we use?  She uses 2014 or 2015 and I use 2017. 

If anyone knows a solution to this, I will be very grateful:)

Thank you, and have a wonderful weekend!

Chunyi