steps:
1a. Open Unity Hub (Note: issue does not repro if you open Unity app directly in Finder)
1b. open a new URP template (using 2020.2.0a16 or above)
2. go to scene view
3. observe low framerate
4. go to game view, then back to scene view
5. still low frame rate
6. enter playmode and exit
7. back to scene view, frame rate is improved

Expected: performance is optimal
Actual: performance is not optimal till after enter/exit playmode

Repro: 2020.2.0a16, 2020.2.0a20 + Hub 2.3.2 ( macOS Catalina 10.15.6 )
No repro: 2020.2.0a15 + Hub 2.3.2

Notes:
- also repro just by opening via Terminal (with no arguments) on MacOS ( see example command on https://docs.unity3d.com/Manual/CommandLineArguments.html )
- repro with templates: 3D or Universal RP
-issue repro whenever Activity Monitor (with View > All Processes, Hierarchically) shows that Unity is a child process of Unity Hub.
- Does not repro when Unity is not a child process of Hub (like when you open Unity app directly)