Basically, if you turn on full-rbf, you might not have a full-rbf peer. The peering branch has code that:
Advertises a FULL_RBF service bit.
Makes sure you're connected to at least 4 other nodes advertising that service bit.
This is good for the full-rbf network, as it ensures we have a core set of nodes propagating full-rbf replacements. I'm running that branch on all my nodes myself.
addnode
in the config without running your branch?