observe() may lead to infinite regress

[waxlamp]

Because the observe() function keeps a reference to the last state, it can overestimate when a change has occurred if an observe self-invokes in specific circumstances. When this happens, it is possible for the system to go into an infinite loop. The loop can be avoided by using a timeout to dispatch the offending action; however, it may also make sense to do so within this function, thus always forestalling the problem.