We think there's still a bug, in ZODB.Connection or ZPublisher/Publish,
but since commit c277ed20, NEO does not
require anymore that Storage.sync() is called in order to take into account
invalidations that have already been received since the last tpc_finish.

IOW, this is not the place for such fix because it's independant to NEO.
ERP5 already ships it for ZEO (patch disabled by default).