So, when you ceate trigger, it auto cretes name like 'table_after_insert' and if you change to before insert it auto changes to 'table_before_insert'
Ok, save, and when you get back to edit later , upper processs does not work any more. It changes type of trigger ! but not it's name.
So, if you don't look you can be easily looking at wrong named trigger, that is forinstance: you are looking at 'after_insert' named, but it is actualy before insert. Etc.
I see someone claiming that would be bad as someone would like to have triggers 'not default named', but same goes for first creating trigger, so if no complaints till now, all OK.