Should invite_state contain the invite event?

https://matrix.org/docs/spec/server_server/r0.1.4#put-matrix-federation-v1-invite-roomid-eventid
https://matrix.org/docs/spec/client_server/r0.6.1#get-matrix-client-r0-sync

The spec does not say which events are required and only gives some recommendations (in server_server), but it looks like element doesn't work without the invite member event in the invite_events

Read the linked server-server invite endpoint and client-server sync sections, then inspect how this specification describes invite_state and invite_events. Compare the stated requirements with the Element behavior mentioned in the issue. Done means the relevant specification text clearly states whether the invite event is required or how its absence should be handled.

Written by the indexing model from the issue text.