Not flown in the sim yet but found this on one of the images on the marketplace for the update and it shows a similar bug if not identical, albeit not against clouds:
Nothing more to add here, except just to say I’ve voted for this to be fixed. I’m big on VFR and taking photos while I fly, so in cloudy/dark conditions, it’s a big deal for me. Of course, I could just fly in midday, relatively clear conditions, which seems to minimize it.
Perhaps there’s an anti-alias setting which can help? Hope it can be fixed soon. In the MSFS World, it’s not just clouds that have a silver lining! 
so true … sad but true 
please @ASOBO, fix this asap, it ruins the realism
I take it back…this blue line outline is constantly drawing my attention and really teeing me off !
Oddly I’m not getting the outline, but I’ve only flown in full sun so far. Wish me luck.
I saw the same at London. There were many players online, and thus many planes buzzing around. But this outline/halo was only present on a few of the planes. Most were fine.
This is issue is most likely caused for the same reasons as with XP11 Enhanced Cloudscape:
Are you actually experiencing this “blue edge” with TAA only, or regardless of the AA mode?
I had already seen this before the UK upgrade, around the Savage Carbon.
At the time I thought it was due to the textures.
It’s got to be something to do with the atmospherics at the time. I flew from Cardiff, to Bristol, then London City, and I didn’t see this phenomena. I even played with the weather a bit, and couldn’t re-create it.
Same issue here, and I’ve got a blue border around my screen. Operating the A320NX on a very rainy, dark, overcast day out of EGKK.
Same problem for me 
Asobo fix one thing, and break another😒
I’ll try an replicate this tonight. I have seen it, even shot a video of it in effect with neat little vapour trails behind buildings as you move the drone camera around. This was all using live weather. I don’t see it all the time, though, and not during clear weather at all, so I suspect some weather configuration cases it to appear. Maybe aerosol density, something like that.
I saw it very clearly while parked on the ramp at EGLC, where you could see it around light stands, and other airport structures. That’s as good a place as any to start from.
That is caused by TAA.
Same issue here, with or without VR.
Nvidia 3090 RTX
To be honest, watching a plane fly by with this vapour trail behind it looks pretty cool. It’s not a new issue, it was there months ago, but only appears in some conditions.