Instead of waiting for it to happen again, I'd just clear the Samsung Account app cache now, then watch closely to see if it happens again down the line.
I have been having this issue as well. This is how I fixed it. Go to Settings/ Accounts/ accounts (again)/ Samsung Account/ About/ App Info/ Notifications/ uncheck.
There may be an easier way to get to the Samsung Account app and turn off notifications, but this is the only way I knew how.