Why are there benzos on in my urine sample?

I had to take a urine test as part of getting a prescription for a controlled substance moved from one doctor to another. They wanted to do due diligence before taking over the prescription.

The drug (amphetamine) was in my urine as expected, but also benzo (it doesn't give level, just a threshold) which are definitely NOT expected.

I have had xanax a couple times while flying; but not in several years. I was reading about false positives; and I am not taking anything remotely close to what might cause it.

In terms of "substances" I don't even have a multi vitamin or something. I take the Adderall; coffee; the occasional cannabis+tobacco spliff; and the infrequent magic mushroom; but everything else going in my body is food.

I haven't even had a tylenol or ibuprofen or anything in months. About 2 months ago I had a tick latch on; and I got an antibiotic dose for that.

I am less concerned about the doctor seeing the benzos and thinking I am a druggie; as I am about actually have benzos in me. Am I getting drugged by my meal kits? Or are false positives just a random thing?