401Ks are so overly complicated. Being a max out saver myself, my understanding is that most companies offer the true up but that is calculated at the end of year and paid beginning of next year. For me the matching contribution stopped but the non matching contribution continued.
Also Christmas might have came twice for you as well as early. For me the 401k contribution applies to bonuses as well as salary so the true up should take that into account so you should get a true up of your bonus as well. Merry Christmas!
