The odd thing is i have experienced the same thing a few days ago.
It was on a location that i previously had a hard time getting sat lock @ 16h local time.
I made the alu shielding mod and wanted to test that out.
Its a rural location, FPV was gone after 5m, came back but i wasn't able to get FPV greater the 30m.
I thought i finally killed the bird with the mods i made because i am used to have FPV showing difficulty's around 1600m.
I rebooted several times to no avail.
But the satellite test was good. I got a lock on the ground were i previously had to be in the air.
If its due to the mod is a question mark because i forgot to record conditions on the first attempt.
Yes sat reception depends on time of day and solar weather.
When i came home and the second battery was still full i toke the bird for a spin in a semi urban environment.
All worked out fine again.
My advice, try to test it in a different location, @ least go to a rural one.
Why i did have issue's with FPV ? There is a major gas pipeline nearby there, maybe it was due to that, not sure but it freaked me out !