Although we have implemented an algorithm that deletes entries when they are not used [1], this implementation presents many limitations and complications.
There is not so much that we can do from our side, this limitation requires an extension to the eBPF maps.
[1] https://github.com/polycube-network/polycube/blob/master/src/services/pcn-bridge/src/Bridge.h#L167-L175
-Mauricio