Hi Emami!
Sorry for the confusion, this wasn't the evening. The evening went the same, he slept for 50 minutes, then 36, then stayed up for an hour or so until falling asleep at around 11. Then woke up at 12:30 etc.
Him flip flopping happened in the middle of the night on multiple occasions. My guess is he trying to practice rolling bc he would not stay put and sounded frustrated. We are currently sharing a room (1bedroom apartment in NYC). He was awake ever hour or 2 all night long. I'm hoping with the stretch of A time, we will both sleep better.