It's not allowed the user to show the ERRANDS drop-down on Review Pending Changes page with Ops Manager release 3.0.39. This happens to any other tile than VMware Tanzu Application Service (TAS). Every time clicking on the drop-down arrow for any other tile just shows/hides the errands section for TAS tile.
Ops Manager 3.0.39
This is a known issue for Ops Manager release 3.0.39, which is fixed in 3.0.40.
Upgrade Ops Manager to release 3.0.40+ to get the fix.