Probably when you go to the Forms View. That is when REP is activated. 

Definitely if you print or e-file. 

There is a counter that will tell you, if you activate it. 

I agree about triggering when print or e-file, but bundle blocks do not count as Rep, there must be something else triggering usage. There was a little counter showing yesterday on bottom of the screen before the update but it is not gone post update.