Fresh start of msfs @ 0200z/6pm pst 22/11/22
PHNG
In sim Winds 060 12G21
West Coast Server
These " Perseid Meteors" 
coming from about 060.
Data(all)>On.
Multiplayer>Live.
Weather>Live, Display Thermals Option> OFF. (checked at the time happened-100% sure off)
Nothing near or around the ground or aircraft.
Update: 0330z/7.30pm pst.
Restart about an hour later= Gone.
Open the Weather Toolbar and turn off “Show 3D Thermal”.
I hope that helps.
Thought of that 
but…
As it’s only happened once, I haven’t created a bug rep.
Similar but unsure if op had ensured off to begin with.
Good to know!
but I was free flight at the time.
Found the cause…
Bug Report here
1-Fresh start msfs. Start a Free Flight & Check Weather>Thermals>Off. Exit flight to main Menu.
2-Select the new Soaring Event Soaring, Como Lake, Italy
But Do Not select Fly Now.
3-Return to main menu and choose a world map flight.
( I used cold/dark start at PHTO, ramp 125 )
Result= The thermals will be visable and Weather Menu>Thermals will be set to On.
Notes:
1- If the free flight is closed after seeing Thermals (Do Not change Weather>Thermals>Off at this time).
and then another new free flight is created= The thermals will be gone & Weather Thermals are back to off.
**It seems to take 2 free flight restarts to clear thermals & return to thermals off, but did take 3 once.
Or a restart of msfs after intial free flight seeing thermals, will reset to thermals off.
2- Selecting Fly Now in Soaring Event, Como Lake, flying a bit and then closing it and going back to main menu, then selecting World Map Free flight= No Thermals, Weather Thermals off.
So, It’s only if you don’t procede to the Soaring Flight, that this will happen on the next Free Flight.
Make sense?
