Sept. 16, 2020 1:30 PM EST: When using multiple Lookup Elements on the same form, the subsequent Lookup Elements will look overwritten by the first. However, this is only a display issue and data is not actually overwritten. This is isolated to iOS iForm version 9.3. We are currently working on a patch to get this resolved.
UPDATE (Sept. 16, 2020 5:00pm EST): The updated patch for iOS 9.3 is waiting for Apple approval.
UPDATE (Sept. 18, 2020 9:00am EST): Patch for this issue is now available in the appstore. Please look for version 9.3.1.