How abnormal/normal is this for a RMS?

[curtthedirt]

I recently flew my rocket on a K - 185 W
After I took it apart to clean the casing I noticed this split in the internal liner. Is this normal?? It was a long burn motor.

 

[Voyager1]

Presumably that was at the nozzle end? I have experienced a similar liner failure. Be sure to check your motor casing for heat damage and/or distortion. In one instance the metal casing bubbled out a few mm and had to be replaced.

 

[cichlidgoob]

I recently had a similar result using a K480. I don’t have pictures but the liner had longitudinal cracks that went the entire length of the liner. I had no “holes” as in your situation, but there were several full-length cracks