An update has just been applied to the practice service. We heard that several times over the last few weeks lap times were not being returned after a lap, and this update should address that. It is designed to increase the consistency and speed with which lap times are returned.
In cases where this might not happen for any reason, we also have better tracking now so we can respond and understand the situation better when it occurs. You may post in this thread if you have any further feedback on practice or even if you want to say it has improved.