According to GitHub's webhook docs, the scope of a membership
event can only be limited to 'teams', which holds true when a
new member is added to a team. However, we just found a payload
in our logs that indicates that when a user is removed from a
team, the scope of the membership is erroneously set to
'organization', not 'team'. This is most likely a bug on
GitHub's end because such behaviour is a direct violation of
their webhook API event specifications. We account for this
by restricting membership events to teams explicitly, at least
till GitHub's docs suggest otherwise.
Eeshan Garg