I would wonder about sitting in the heat too long being the cause of a failure. If that is true, it's because the fit of the tubes were not right for those conditions, not because of the altimeter.
My suggestion would be to get the fit of the tubes correct for the worst conditions and then adjust with tape, etc. when the conditions aren't that bad.
Just like motor eject with a nose cone, most DD rockets don't really need much friction fit at the av-bay/booster joint. I know most use shear pins there, but it isn't really needed. If you can pick up the rocket without it falling apart, that is enough friction to keep it together at motor burnout since the air drag force is largest against the nose cone, way more then the drag of the fins. In most cases, no friction in the joint between the upper section and the lower section will still work just fine. Certainly enough friction and/or shear pins to cause an apogee charge to fail is way too much resistance for that joint.