I think you can reproduce the issue following this steps:
1. In a new project with just one frame create a Tag
2. Make a new frame (it will be inserted inside of the Tag)
3. Change the Tag just to the first frame and create a new Tag to the second
4. Ctrl + Shift + E to export. Choose in "Frames" one of the tags and in advanced enable "Include frame tags in the file name" and export
Results: I've had experiences where the tag name entered was the wrong name. Now no tag name is being entered.