If I try to import some GIFT questions which have 

// [tag:equipe]

I get a pointer to https://docs.moodle.org/39/en/error/moodle/dmlwriteexception#dmlwriteexeption_error_when_importing_quiz_questions

I validated the file format (it's UTF-8).

I found a MWE of a single question that won't import on my Moodle. If I change the tag to [tag:team] then it works. Don't have much time now to play around with other things, but I did try to see if it was a problem with category/tag similarity but that didn't matter:

(see attached - the text editor here keeps changing it if I try to put the GIFT here)