When a parent component and its child component both re-render (e.g., both have subscriptions that fire simultaneously), event delegation permanently breaks. Events stop firing because the VTree's VComp.child reference points to a stale child VTree that doesn't match the actual DOM.

1. Create a parent component with a subscription (e.g., M.subs = [someSubscription])
2. Nest a child component that also has its own subscription