Multibody constraints of links with no collider do not get solved

[Scorg]

Constraints on links or base that do not have a collider return -1 from getIslandIdA() or getIslandIdB(). Island management seems to be filtering them out when merging islands, and they never get added to any island.

I suppose this is undesired behavior because I haven't found any comment stating that colliders are required.

Edit: Forgot to mention that overriding getIslandIdA/B to return some existing id (I used the base collider's id) does make the constraint get solved.