I just installed Teamviewer 14 today on my Windows 10 machine (have had it installed on other machines before, so not my first rodeo), so I'm at latest version of 14.6.4835. Client I'm working has a Mac OS that he JUST upgraded to 10.15, Catalina (just came out 4 days ago). He installed Teamviewer while I was on the phone with him so he has the latest version. But I'm guessing we are dealing with a bleeding edge issue.
I can connect and see his top white bar with the black apple menu icon on the top left and the Finder or other conect menus but I never see the drop down and I just see grey desktop instead of his apps or launch bar or whatever should be there. Basically a desert of grey with a white bar on top and some black text.
What I'm wondering is two-fold.
The same issue here with mac (os 10.14 - Mojave) to mac (10.15 - Catalina).
The solution "Screen Recording"
I hope this help you.