I assume you have Laser Rifle item defined twice in the ruleset (once the ruleset you sent me and once copypasted from vanilla ruleset).
Depending on file order and "rng", the game loads the vanilla ruleset second and overwrites your definition, making the Laser Rifle ammoless (as in vanilla).
This then displays the power bonus 15 defined on the weapon.
The STR_LASER_RIFLE_MOON is only defined once and is not ammoless.
The power bonus is displayed from the compatible ammo STR_LASER_CELL... and is correctly empty.
The power bonus from the weapon is ignored, because it's irrelevant (damage comes from ammo, not from weapon).