CBD and drug testing.

[Adorable45Deplorable]

I quit smoking cannabis a month ago and last night tested positive for thc.
I've been using Naked CBD as a tincture(wouldn't recommend.) I'd like to smoke cbd flower or use a full spectrum tincture but was playing it safe as I read the less than .3% can still make you pop hot for thc.
I got the naked cbd vape juice/"tincture" cause on the box it said "NO THC."
Is it possible for cbd isolate to metabolize into thc. Do you think the no thc part was false advertising?
I was under the impression that 30 days abstaining would be plenty to piss clean so I'm trying to figure out what the problem is and have hope when I get retested next week ill be good.
Thanks for any input.