The phrase "strange quirk" means a peculiar or odd behavior or characteristic that is unusual or different from what is considered normal or expected. Full definition
By strange quirk, his family abide by a strict no music policy, down to a romantic altercation from a few generations past. (lwlies.com)
While the most brilliant business minds on Earth often possess strange quirks, a glimpse into the intergalactic future as envisioned by Elon Musk paints a rather harrowing — and thought - provoking — picture. (entrepreneur.com)
Of course this Ozarks farm chick has many strange quirks. (missmustardseed.com)