Unable to re-share Shareable
A leaves, sends REMOTE_LEAVE to B and goes into LOCAL_LEFT state. Now B also leaves and since it got the leave message from A, it does nothing, just moves into START state. Provided that A and B get access to the forum again through other contacts, B can still share the forum with A while A is permanently blocked from sharing it again with B, because it is stuck in the LOCAL_LEFT state.
https://code.briarproject.org/briar/briar/commits/shareable-re-sharing-issue