It's hard to tell for sure - a video would be more definitive - but to me it looks like the threaded ferrule that the PRV screws into is leaking at the lid interface - ie, the weld around the ferrule has a breach.
But that would be a less frequently occurring failure compared to a leak between the PRV body and the ferrule - which might indeed be resolved by tightening the PRV in ferrule.
If the former is the problem, the three options are replace the lid ($20 from morebeer.com plus s&h), silver solder the breach, or have someone TIG it...
Have you pulled it apart and cleaned it? Most of the PRV are plastic, swap with another and see if it's the plastic valve threads or the metal lid threads. Then swap a lid and repeat. Replace whatever part fails
FWIW, the threads don't seal pressure. Only the o-ring seals pressure. O-rings wear out. Keep spares around, they are cheap, cheaper than leaks. I think the last bag I bought on Amazon was about $9 for 100 of the PRV. (they also fit some poppets)