Depending how accessible the spot is, I would probably soak the area all around the tube at that spot with thin CA. Let it sit overnight, call her done. Tube coupler with wood glue or some such will also work but depending how far in it is, might be tough to do without getting the coupler glue-locked before it gets to position.
I understand this is on the main body tube, and you've already got the motor mount in, so access is from the forward end, I guess. How far aft from the forward opening is the problem area?
If it's hard to access, you could always make a pinhole and dribble in the thin CA through it, then rotate the tube to spread it around. Or sand the glassine off the area and let the CA soak through.
Or you could just ignore it and probably it would work fine too. I've found primer and paint can be close to a structural element in these birds!
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