Somehow saving a custom 'Run As' acount under Hybrid worker group settings (automation accounts) does not persist and after refreshing the page the 'saved' custom selected account is back to 'default'. Permissions are verified, save button reports no error.
I ran into this issue after adding/creating a new hybrid worker, but when changing the Run As account for pre-existing hybrid workers that worked fine intially also fails now to change the Run As account. They all revert to 'default' instead of custom account after saving.