Reasons why a bolt won't fully close intermittently???

C93 Pistol

I recently purchased and have going through some checks before taking it to the range and found that more often than not (say 4 of 5 times) when the cocking handle is slapped free to charge that it fails to fully close the bolt. When this happens I can close the bolt the rest of the way with my thumb on the bolt serrations with a nice snap as it closes.

Some specs

AS PURCHASED-#8LP and 0 (8mm) Rollers
Bolt Gap - .010"/ 254mm
Cocking Tube Gap-.041"

FIRST CHANGE- #15LP and 0 (8mm) Rollers
Bolt Gap- .013"/330mm
Cocking Tube Gap-.041"

LAST CHANGE- #15LP and +4 (8.04) Rollers
Bolt Gap- .017"/432mm
Cocking Tube Gap-.041"

The bolt closing issue has remained the same through all the different LP/Roller combinations. I'm a bit confused that the Cocking tube gap has remained the same with different bolt gaps? The C93 pistol is a bit different when it comes to measuring the cocking tube gap as it rests right at the rear cut out in the tube. I measured end play with a set of calipers as the charging handle was moved front to rear. Fwiw the cocking handle has about .380" free travel outward until it meets resistance to cam the rest of the way. The recoil spring seems to have good tension, but that's subjective to feel at this point. With the gun apart, the carrier slides free down the rails to the point where it contacts the trunion.

Is there anything that comes to mind on the bolt not fully closing issue that I should look at? As the bolt gap was changed with the different LP/Roller combinations shouldn't the Cocking Tube Gap have mirrored the changes also?