Using pulla bung, I caught a fish and needed to pull the elastic out to land it. A big air bubble about 2cm long appeared in the elastic about 2ft from the end nearest the bung. I managed to push this down to about 4" from the end, cut it off and retied. Its only the 2nd time i've used this top 2. Anyone any idea what caused this? + will it be ok to keep using it or would it be recommended to change it?