any idea what might cause this error....our site users are regularly experiencing errors the past two days that match these errors from the logs: "status":404,"code":"ERR_RECORD_NOT_FOUND","message":"Not found","serviceControllerName":"Categories.ServiceController"

It sounds like your users are trying to load a commerce category that does not exist. It could be because someone has deleted it. You should track down which category it is, and then check the record in the backend and see if it's there and has been configured properly.