I seem to be unable to use text shortcuts (System Preferences -> Keyboard-> Text) in any of the betas of DT3. Is this a known problem?
thanks
Welcome @SD22
No, there is no known issue with this.
I’d deselect any files and check if you have Preferences > Editing > Text Replacement enabled. After enabling it, select the file and try it again.
Text shortcuts are completely unreliable over here in all apps. Usually they work but sometimes not. This can even happen right after logging in or rebooting. Each time I check the setup in system preferences and it’s the right one. And sooner or later it starts to work again. Why? No idea 
One possibility, which came about after a similar problem I encountered with Scrivener, is that the feature in the app, to which the shortcut applies, has to be used first. If the shortcut is to do x, then apply x via the app’s menu to begin with.
Most of the time I have no problems using text short cuts in third party apps such as Things or in first party apps such as Notes. I also do not recall having any problems with DT2. ¯_(ツ)_/¯ (or Safari technology preview). Occasionally there are problems but that seems to involve syncing between devices.