Tube filament brightness

Hi everybody. Just have a short question. Recently bought Shuguangs 2A3C matched pair. And noticed that one tube has brighter filament (see picture). Both tubes seem to play fine except that one with brighter filament gives slightly louder background noise, only heard when the ear is close to speaker. So is it a problem with that brighter filament? Tubes have been broken in for 20 hours by now. Thank you in advance for your answers.

1st you need to switch the tubes around. If the same tube glows brighter on the other channel, it is a problem with the tube and I'd contact the seller.
If the other tube glows brighter on this current channel, your amp has an issue.
It is fairly common to see difference; that is that the openings/area is different, not that the glow is different.
Remember: tubes are handmade.