“Cancelled” has been a perfectly acceptable spelling for “canceled” for a long time. It’s not the preferred by all dictionaries but it’s listed. It’s usually the British spelling.
My pet peeve is the acceptance of “irregardless”, though it is listed in dictionaries as nonstandard.
I despist the creep of of”T”en where the t is no longer silent. For those of us old enough to remember, prouncing the T was seen as being illiterat. (see “aks” vs ask.)