Can't get into first after reverse

Zolfix

I picked up my 6MT 2010 370z a few days ago. I searched all over and could not find anything related.

This has happened a total of 3 times so far. I try to do a 3 point turn and after backing up I can not get into first. The shifter will go there and it appears as if it is in first (the indicator even shows it is in first), but when I try to get going (1200 rpm and clutch to the contact point) the gear just casually slides right out into N. No noises or anything like that and the car does not move as if it was in neutral in the entire time. Yes, I definitely push the gear in all the way when I try to get into first. I end up having to start in second since I am in the middle of the road at that point and people are getting pissed.

So far this has only happened right after backing up. Any ideas?

I also have an odd chatter coming from the rear when slowly (1200 rpm) launching the car in 1st, while slipping the clutch. Not sure if that is related.

Loving the car so far except for that issue!