Torch gap gets smaller at the end of gantry

My torch seems to slowly get closer to my sheet of steel at the end of my gantry. I have leveled, measured and tightened the bolts several times. I can use the larger spacer and as the gantry returns and the gap almost tripled. When the gap stays consistent it only stays that way for a few projects then the torch starts touching the metal again.

Water table and slats are level.
Gantry arm level
Torch secure.
Clamped metal down

It’s just frustrating to get a couple cuts then have to adjust everything again.

I’m a mechanic by trade and I’m not a complete idiot.

Are all of the adjustable bearing block bearings touching the rail? Are at least one of the two bearings per fixed bearing block touching the rail?

Thanks for the pics. Here’s how to fix it. Break loose the black cap screws that secure the adjustable bearing block and then slightly tighten them. Next, turn the black set screw clockwise until both bearings are in contact with the rail. Then re-tighten the cap screws. Do this for each bearing black that has a non contacting bearing.

Thanks for the help!