Father Servo time limit?

[Ⱇⱃⰰⱀ iliti Вран]

Tried beating Father Servo level 50 with my 2B being level 16. Yeah, someone had to do it earlier or later I guess. Well what actually really confused me if this fight has a time limit? I've been fighting him for about an hour and half maybe, and finally dropped his HP on about 50%, after which the fight ended. Was I killed? No. Was Father Servo beaten either? Well, obviously... no. He stopped fighting and the wall surrounding us disappeared. He said something about enjoying his might and that I may fight him again if I please.
Does this fight have a time limit or is it meant to be this way? This is absolutely weird, definitely did not see this one comming and it got me really confused since I though the only way to lose against Father Servo was to let him beat you (drop your HP to 1 single point) which didn't happen. It's obviously not even about the total damage I've taken since I'm playing on Hard so pretty much any hit would've been lethal I believe. Any reason for this? Is it because I'm underleveled?

[Aemony]

You know, I think it might. I remember experiencing something similar once, where the fight was suddenly aborted when I got him down to 5% HP or so.

Never found out if it was due to time limit or not, though, seeing as I hadn't been in the fight that long yet.