You know, you will seldom get a group of boyers to agree on any one subject so every bit of advise is well intended, but purely speculation.
Are you possitive that the was set before stringing? if it sets long enough, it will cure without heat, but if your box didn't get hot enough and you strung before it was cured, it could delaminate.
I remember in the beginning, my wife shut the lights off in my first shop and she didn't know that it cut off the outlet to my oven. No problem, just cooked it later but If I hadn't known, I might have strung it too early. Just thinking out loud.
bigjim