Is Mixed Martial arts teaching me bad habits?

I wish i could help you, but I'm really perplexed, flabbergasted and dumbfounded with your question.

Self defense and fighting in a combat sport are two different things. Most of the skills you learn in MMA are applicable to self defense. But there is a gap because of the focus on competition. How long have you been training? Have you fought at an amateur or professional level? How different are the two of you physically?

I don't know your skills, but you need to measure your own progress. Just because someone goes to train regularly doesn't mean they've gradually increased their skills over time. I have over four years of grappling experience, but I'm still a white belt. Part of that is inconsistent training due to life circumstances, but it's also because grappling is hard for me to learn.

Another thing to consider is that just because someone is untrained in technique doesn't mean they lack strength, power, reflexes, flexibility, and so on. One can't casually compare the skills someone may learn from another sport or fitness training, but most types of training have at least some benefit overall. Those things can carry over to other activities like combat sports even if the person is lacking in technique. We can logically assume a fighter punches harder than a powerlifter. But we shouldn't be clueless enough to think the latter has no power just because they lack technique. Most people can block and dodge punches without much training.

Training increases ones chances of success. It doesn't mean you'll beat everyone you encounter with less training especially if you aren't at an advanced level.

Maybe your coworker understated his abilities to you and suckered you.

It sounds more like your partner is a natural talent and/or you are a great instructor.

This tends to happen in sport oriented martial arts. You inadvertently trained yourself to expect and react to certain behaviours from your opponent who train the same style. Suddenly, you're faced with someone who does things unorthodox to you, and your body doesn't know how to react. I've seen it before with sports karate guys..... they tend to fight with their left side forward, so the odd time they encounter someone who fights with their right side forward it screws them up.

You talked about trading punches. That's not MMA. In fact, that's not a martial art. It's easy to dodge or block a punch for anyone that has good reflexes. Next time you spar with him, try taking him to the ground as one option. MMA doesn't really follow boxing rules.

I agree with Anonymous. Your coworker may be lying.

Next time take a sharp object with u
And stab him.
Because on the street that how it is.
No one will trade punches like that