Can not clearly see the bubbles you speak of. Are the bubbles in that black streak that runs through the graphic? Normally, bubbling is the first stage of delamination of the fiberglass from the sandwiched wood caused by water leaks which dissolve the wood product releasing the fiberglass where it is glued to the wood. If caught early enough and corrected it's not fatal, but left go it can turn into a cancer. If this is the case and you're not versed in fiberglass repair, it is best left to professionals.
'07 K3500 Silverado LT Crew Duramax (LBZ)
2016 Salem 27RKSS
1984 CHEV SCOTTSDALE K20 2GCGK24J0E1XXXXXX (Chevrolet Legends-Class of 2019)
"...exhaust fluid? We don't need no stinkin' exhaust fluid"