.ai files won’t open on Illustrator for iPad

I have a recurring problem where I can not open .ai files from adobe stock in illustrator on the iPad. However, it isn't all .ai files, only some, and I haven't noticed any similarities with the files that won't open- it seems random. I don't get a specific error code, it just says "Can't open file xxx.ai" so I don't know what exactly isn't working.