Formerly reliable BCM 11.5" upper has sudden cycling issues

What’s your build list? Is this a bone stock BCM upper? Any mods? BCG specs? Round count?

It’s made from all BCM parts that I assembled. 11.5" LW barrel, BCM gunfighter comp Mod 0, .625" gas block, upper receiver and BCG. The rail is a 10.5" MI SSM FF M-LOK.

No idea of the round count, but it’s in the multiple thousands.

Bcm gas tube?
Approximate round count?

Crazy how that works.