I disagree regarding the owner.
From OPs description of events the owner doesn't even know wtf ACTUALLY happened when OP went in the prior time. He wasn't there and it isn't clear that any other employee saw the interaction either.
Do you think the employee that intentionally prepared an order wrong, then refused to fix it, was honest in how the interaction went down? Of course not. So owner is told by an employee that a customer was being a jerk.
Given the issues with the first employee, I doubt OP was his normal self with the second employee, who hadn't seen the interaction, but obviously knew OP well enough to pass along that the incident involved OP.
Owners picture at this point is:
From the first employee: Customer came in and was a jerk.
From the second employee: That customer was OP, there was obviously a mistake with the order, OP wasn't acting like usual, and they corrected the issue from an order stand point. But this employee likely couldn't clear OP.
The owners understanding of OP: It didn't jive with whatever the first employee said.
So you seek information from the other party. The owner is in a no win situation, because he doesn't know everything about the situation. He could blindly believe his employee about OP and lose a good customer because of a bad employee. He could ignore his employees and potentially promote having toxic customers that piss off his employees. OR he could take a middle ground and get more information.
Everything up to the interaction with the owner, OP is definitely NTA. The interaction with the owner is firmly in the INFO territory.