a mix of the words mayhaps and happenstance
which in turn are a mix of the words maybe-perhaps and happen-chance
together it means : perhaps, maybe by chance /he/she/it just happened to be that...
mayhappenstance is used to save time speaking except when the other person asks for an explanation hence more wasted time trying to explain and thus being ironic
Okay, mayhappenstance I was high when i thought of this, im not sure 100% sure, I'm just saying that mayhappenstance it is.