I've gotten in the habit of pressing down on the cannula patch during a bolus just to make sure the cannula is fully in. This after some dodgy partial insertions in my early days.
Just now I did this and got an occlusion alarm and delivery stopped. Possibly I pressed too hard? I was suspicious of this cannula anyway, as it seemed to be playing up, and of course I replaced it after this alarm.
I just wighle a little bit when putting them in and press firmly on the needle to make sure its comfy and going to work... Even on my bum I can , if too near my front it seems, hit bone despite only being 6mm cannulas.
Any slight pain and my body will be to to blame and I know the set will deliver slower or occlude.
If you are running at good levels you should not have to worry about bolusing.
Yes I think you might have set the alarm off pushing down. Sometimes the set is near a muscle, bone or vein and it's ok as long as you don't mess with it. I've had a good set fail because I lay on it in bed and the pressure must have caused it to hit something or kink. I'm told you can kink Teflon sets once in if you're not careful (although much harder to do than kinks on insertion). I know it's hard but if BG is good after set change you need to trust the set and not push when bolusing.