Uninstall DJI GO 4 v4.1.0 and do a fresh install of DJI GO 4 v4.1.2. Rechecked all setting in the the GO 4 App. Did find some setting changed back to DEFAULT and reset my setting back to normal usage. Tested the Zoom in/out Function of 5D button and it's working just fine.

Equipments & Firmware use for Test:
Samsung Galaxy S6 Edge+ [Android Version: 7.0]
DJI GO 4 v4.1.2
Mavic AC - firmware v01.03.0800
Mavic RC - firmware v01.03.0800

All my Hardware Equipments had Updated to new firmware v01.03.0900.

Zoom in/out function working as well for GO 4 v4.1.2.  Mavic AC+RC+Goggles firmware v01.03.0900. Had not encounter any problem upgrading all my equipments to the new firmware v01.03.0900. Checking all my setting before Test run the firmware and software equipments turn on. Everything's seems to working normal as far as i can tell. Will test flight mavic with the new firmware update coming weekend.