Flink has suffered a regression due to
FLINK-7294. Any attempt to accept a resource offer that is based on unreserved resources will fail, because Flink (as of FLINK-7294) erroneously insists that the resource come from a prior reservation.
Looking at the original issue, the problem may have been misdiagnosed. Ideally Flink should work with both reserved and unreserved resources, but the latter is a more common situation that is now broken.