Unable to interact with other programs
I work on multiple PCs where this has happened. There are some times when I'm working in CC2019 that I'll try to interact with another window (a Chrome window, Premiere, etc) and won't be able to. I will only be able to interact with After Effects. The only way for me to fix this is to hit CTRL-ALT-DEL. After that, I have functionality in all my programs again. This only seems to happen when I'm using After Effects. None of the other programs do this.
We really appreciate your post, however, User Voice is primarily for feature requests and bug reports. It appears your issue is more of a troubleshooting problem which could be solved more easily by our support team. You can open a case with them via call or chat at this link: https://helpx.adobe.com/contact.html