On 1 Jul 2019, at 11:43, Jacob Carlborg wrote:

I just installed the public beta of macOS Catalina. I’ve noticed that the TextMate icon is missing in the Dock. It’s showing a generic application icon instead.

Almost certain that this is a local issue, some sort of caching gone wrong.

You may try to touch TextMate.app and all contained files, but maybe easier to just delete and re-download the application.