This reproduces locally for me.

I think the root cause is that we carry the same $task through the edit into the re-render, but its projectPHIDs are never updated (the edge transaction doesn't know about the attachment point). We could resolve this by making the edge edit update the projectPHIDs (but this seems involved / complex / hard -- probably requires formalizing attachment points substantially) or reloading the $task explicitly before rendering (this is probably simpler).

The card rendering logic currently does an explicit manual reload of project PHIDs to resolve this. We should unify the card/item rendering logic, and probably just do a full reload in both cases.