I am hoping someone can help identify what is causing the display glitch after a boolean.

Don't know why but our inventor Michael will find it...

If you rotate your cylinder (the lower one), the problem is out.

I think it's a alignment problem.

Perhaps a problem with these egdes ???

Ah - I always forget about seams. Thank you for the reminder.

There is a handy merge command that is useful for joining edges that are already part of a solid object. Sometimes this simplifies things, so worth checking out.

TIL about the merge command... wish I had known about this a year ago. That's what I get for not reading about commands with no UI button. Thanks nameless!

Hi Charlie, it seems to be a glitch in the display mesher on the top face. Your actual model seems to be ok, if you go to export it out it should export ok the bug looks to be only in the display of it.

I'll put it on my list to investigate to see if I can improve the display for this case.

- Michael

Just rotate all the cylinders for "unaxe" the curve generator before the boolean Diff and all will works fine! ;)
I have remarked that many many times!