Hello and welcome to the forum! Can I just ask, how long has your son had his pump, because if you’ve managed to last 2 years with only one cannula failure then you are doing amazingly well! Yes it happens sometimes, don’t beat yourself up about it, you sorted the problem out as soon as you realised something was wrong and that’s all you can do.
Unfortunately with type 1 it’s impossible to have perfect numbers all the time, as a mum that doesn’t stop you trying I know, but you do get some days where it all goes wrong and you just have to try again tomorrow. If you can see a reason for the problem that’s great, sometimes you can learn something from it, sometimes you have no clue what happened which is a lot more annoying but c’est la vie! You are doing a great job 🙂
If this turns out to be an isolated incident then I wouldn’t worry about it, if it starts happening regularly then maybe you could investigate whether there are any different cannulas that would suit you better.
My daughter is 14 now and starting to take over control of her own diabetes. Attached is a photo of her Dexcom track from the last 24 hours. Last night she had a reading of HIGH for over an hour, she did correction doses but it was only when she started to get undressed at the end of the day and the cannula came off in her hand when she removed her t-shirt that she realised what the problem was. Oops. New cannula and another correction dose later it all came back down again, then went a bit too far and she was low most of the night. Possibly we need to do some pump adjustments but we also have female hormones to deal with at the moment which tend to make her drop. And so it goes on! So far today numbers have been better, let’s hope it stays that way for a while!