This seems to be my day for offering up theories and ideas that have no evidence or proof to substantiate them, but I believe that HBG may succumb due to C&R far easier than native BG. I will find a floater or two a few days after nearly every outing now, even when I know that none were hooked deep, or otherwise injured.
I also believe that the condition is worse when the water temps are higher, and when the fish are larger/older.
In your case Jwwann, the fish was probably injured from the deep hookset. I didn't have any troubles with unusual morts until the fish got some size/age to them.
