If there is a felothar the steadfast, and another creature with more toughness than power, for example and unhallowed phalanx, when the unhallowed phalanx attacks, it will deal 13 damage regardless of if you remove the felothar the steadfast during combat or not. This was on the pc version. The expected result is that the phalanx should revert to having 1 power since i removed the felothar before blockers were declared, but it wasn't until after combat ended that it went back to having one power, despite multiple steps changing and priority being passed multiple times.