Air bubbles are a vexing problem for all insulin users (pump, pen or syringe). Every step in the cartridge filling process can introduce air bubbles, and more likely than not, you have air bubbles in virtually every cartridge fill (you may not see them!). I know I do! IMO, all you can do is minimize them and be on the lookout for if/when they enter the tubing.
I have been pumping for over 16 years and I still get them.
The single biggest successful step I have taken is to fill the new cartridge 12-24 hours in advance and let it sit upright until it's time to load into the pump. This helps all the bubbles to rise to the top, but it is not fool-proof as plastic is very cohesive to air in the cartridge.
The acts of inverting the insulin vial and drawing insulin into the cartridge will create air bubbles that are too small for the eye to see.
When I find bubbles in the cartridge days after I have loaded it, I just periodically pay attention to whether they have migrated to the business end of the cartridge, where they might enter the tubing. They rarely do, but if so, I just monitor and when they get near the infusion site, I prime them away. Normally, it only takes a small amount of priming (less than a unit) to clear if/when this happens.
I laugh sometimes at the instructions I received from my pump trainer to flick the side of the cartridge with my finger to get the bubbles off the sides/bottom of the cartridge, because with some bubbles, no amount of flicking will make them budge ... and then my finger hurts! Also, the flicking generally creates more micro-bubbles. This then makes some bubbles seem to disappear, but eventually they come back.
I also agree that none of the things mentioned by the Mini-Med folks has anything to do with air bubbles and everything to do with being in a call center with a script to follow - sigh!