Can you add a video showing the issue? and some steps to reproduce the issue…
We are unable to reproduce this bug.
Are you on MAC or Win? Does it happen with all documents?
You can add a video to WeTransfer/Dropbox etc and add a link here as comment.
Also, please confirm if your issue is similar to one mentioned here.. https://indesign.uservoice.com/forums/601180-adobe-indesign-bugs/suggestions/31964464-blending-effects
I'm having the same problem using CC 2017