A lab-produced virus can mutate "naturally" in a human host. That changes nothing about its source as being from a lab. The new variant JN.1 is caused by just one mutation on the spike, L-to-S (L455S).No....it's just natural mutation and evolution of this class of virus. There's some nasty ones coming. I've gotten a booster before Thanksgiving and plan on another next fall. (Basically an annual booster much like the flu)
So far...this strain is not taking the world by storm and since we don't have a vaccine for it yet not much to really do. Thankfully it's incubation period is short. So we can avoid sick people and be OK.
The SARS-like coronavirus Rp3 at position 455 is already "naturally" 455S. Thus, human JN.1 is mimicking the bat's "natural" state of infection. JN.1 evolved from Omicron. Omicron's origin is said to be mice, as we've already posted USMB.