What happened!!?!?

I had 42 in puzzle rush survival! I had made no mistakes! So- saying that I had made 3 mistakes and then the rush ended is not true... I come back.. and it says "session has ended"!? I check my best results... It's not even on there! It still has the 40 of a while ago!

Rush in Survival has a time limit, so if you leave and come back you may not be able to continue. I would have to look to see if I can find a reference on that but it might be 8 hours.

edit: it is 8 hours

But that doesn't make sense! Then I would have a new record of 42!

And- I think I have been gone more then 8 hours some times and came back and I continued my progress!

So, can someone please tell me what happened?