P: Hang while using Shawdows/Highlights tool with the Histogram panel showing (macOS)

Latest update fixes the problem. Worked for me.

I had to sign out of Cloud Services and sign in again for 21.1.1 to show up.  Then it updated.

It's fixed. Using 21.1.1 from cloud and the update was automatic. Thrilled

So where's the update? I just checked in and 20.1 is still the latest

I guess you are right, he was polite and probably enthusiastic and for that I am truly grateful. The problem, as you say, lies in the training of on-line support staff and maybe Adobe, together with many other software companies need to beef this up.

I have Shadows/Highlights set as an Action and occasionally use it while editing live football matches. I have noticed that it is crashing Photoshop and the only way to stop it is with a Force Close.

My Ps version is 21.1.0 and I'm using a 2015 MBP with 10.14.6

(German Version of) Photoshop 21.0 to 21.1 crashes whenever I adjust highlights/shadows and the histogram-window is open. OS is MacOS X Catalina, Computers are a new iMac and a Macbook Pro (both late 2018).

I feel your pain. Another inept "technician." He was probably very enthusiastic, polite, yet poorly trained. Adobe has a huge problem with quality control and tech support. But, to be fair, let us all acknowledge how complex the software is--a whole suite of integrated applications with enormous power. None of us can claim to be experts, despite how well we use the software, as there is always something new to learn. But, for the price we pay--year after year, support should be flawless.