sync failed. The requested parent profile (tcp) was not found. upgrading two boxes from 11.2 - 11.6

I had almost the same issue when upgrading from 11.3 to 11.6, on one of the two devices the parent persistence profile "source_addr" was missing so synchronization was failing ... Two options to solve the issue : either force-synchronize the device with the correct profile to the other device, or edit manually the bigip.conf to add the missing parent profile ...