I've encountered this issue too.
Try to add $(ARCHS_STANDARD) to VALID_ARCHS in Build Settings.
Steps:
Build Settings -> User-Defined -> VALID_ARCHS ->
add $(ARCHS_STANDARD)
here's more info in stackoverflow. - https://stackoverflow.com/questions/63391793/xcode-12-build-target-in-wrong-order/63405201#63405201
Environment: Xcode 12.2 beta3