I just recently updated to 2018 from 2017.
I frequently use " Interpret Footage > Invert Alpha " on a Footage item to easily create a matte from existing .mov's and .swf's. Invoking this command in 2018 does nothing. This saves so much time from manually creating a matte in other manners, it's pretty easy with other methods so I'm not — but it seems this functionality was broken and it saves so much time! Anybody got and idea what the deal is?
I cannot for the life of me find where to open a support ticket for AE here but I'm also exhausted so apologies ahead of time.
All in all 2018 works fantastic, I am so pleasantly surprised. I was able to continue an in-progress project from CC 2017 with no problems besides this, which is ******* amazing. The timeline and interface acceleration has got me excited for what is around the corner, great job guys! Reloading my workspace works like a charm and using Kbar script no longer crashes my AE, I can't tell you how much frustration this saves me on a minute by minute basis.
Mac OS Sierra 10.12.6
I'm glad to hear that it's working well for you.
I am also enjoying the newer version.
To report issues like you describe directly to the After Effects team, file a bug report here. You are unlikely to get a response, but you can be assured that when you fill that form out correctly, it goes directly to a member of the AE team.
If you want support of a technical nature, you can contact Adobe support at Adobe.com/support. However, at the part where you're specifying what software you need help with, you DO NOT click on After Effects. First click on Creative Cloud and THEN you click on After Effects in the next area. Confusing, I know.
I'm able to invert alpha using Interpret Footage. Can you try a new project and see how it behaves? Please let us know.