I have a baofeng UV-5RA which doesn't seem to receive properly with my j-pole antenna. my dad's radio (same model, different firmware) receives without a problem, so it's a radio issue. if I go into the menu by pressing the menu button, suddenly it receives perfectly and has no issues, but the moment it leaves the menu it breaks again. sometimes some signals can make it through while not in the menu, but it seem's random. any baofeng experts know what's going on? my firmware version is "HN5RV011FB297" (strange, I know.) my dad's is "BFB297". also, my radio works just fine when using my basic nagoya NA-701 antenna.
Answer: contact the seller.
I doubt the J-pole is the issue; you didn't mention about how it acts with its stock antenna. But their QC is not all that good, and anyone selling them knows it.
I had one where the earphone jack wouldn't work so I couldn't use CHIRP.
The seller sent me a new body with no questions asked.
What kind of pigtail are you using to connect to your jpole? I would imagine your SMA connector is probably cold-soldered or broken, and is held in place by the rigid connection of the stock antenna, but is allowed to move and open the connection when you use a pigtail.
Baofengs are absolute garbage with awful build quality and almost no quality control. You get what you pay for.