[Edgar Poe]

Sounds to me like the tapes have been wound too tight and sat too long.
I advise rewinding tapes periodically and wind them slightly loose. If wound too tight, you can also get two problems, layer to layer transfers, and layer to layer adhesion. Neither is good. If you can't push on the edge of the wound tape and compress it slightly, it's too tight. I know smooth wound flat sided reels of tape look cool, but they are not always wound right and can be troublesome.

Ed