Error in filenames with non alpha numeric characters

[Anastasia]

I’m not sure how recent the change is, but that’s answered in the Bulk Import Cheat Sheet, too:

The docs say I can’t do XYZ in my spreadsheet, but I’ve done it before without a problem.
Wildbooks are always being improved as a result of testing and user feedback. Sometimes this means that we have to make changes to old processes to make way for new ones. We do our best to keep our docs updated to reflect the most up-to-date information on using Wildbooks. When in doubt, check the docs or post in the Community Forums for guidance.