And this morning Trump is going extra crazy on Mueller.
Came across an interesting hypothesis yesterday. It's not clear that Manafort and Trump ever ended their joint-defense agreement, even after Manafort pled guilty. So it's possible their lawyers have been exchanging information throughout Manafort's "cooperation," which includes the period during which Trump submitted written answers to the Special Counsel. Almost immediately after those answers were submitted, Mueller says that Manafort has been repeatedly lying to prosecutors (an accusation he can presumably prove) and recommends immediate sentencing. If the lawyers for Trump and Manafort were sharing information and coordinating answers, Trump may have submitted false statements to the Special Counsel last week.
My gut feeling is that Mueller has known about Manafort's dishonesty for more than just a few days, and he may have intentionally waited to drop this hammer. It's possible we never find out the whole backstory here, but the timing sure is interesting.