Again no logs, since it’s simple to reproduce. Just use Knock Back against a target that can’t be knocked back, in a context that would otherwise result in ridiculously high odds of success, and those ridiculously high odds are still displayed as the topmost piece of information before committing to an attack.
There are two variants of this.
One is when attacking a target (e.g. a giant orc) that is immune to being knocked back. In this instance, info about the immunity is displayed, but it is at the very bottom of the text, whereas the odds that would apply in the absence of the immunity (usually high) are still displayed at the top, so that many people would immediately commit to the attack without reading the rest.
The other variant is when a target cannot be knocked back because physical objects (other fighters or trees/shrubs etc.) are in the way of the target being knocked back. If one object is immediately behind the target, the target can still be knocked back onto one of the neighbouring tiles, but Knock Back never succeeds when all three of the tiles behind the target are occupied by physical objects. Despite this, no warning text is displayed, and the odds that would apply in the absence of physical obstacles (often exaggeratedly high) are still displayed as the topmost piece of information.
If a target cannot be knocked back, due to immunity or physical obstacles, it would be better if the odds were displayed as 0% and if a warning about it was displayed at/near the top in large/bold/highlighted text. If the attacker has the Shield Bash perk, perhaps it should still be possible to injure and fatigue an opponent that cannot be knocked back because of physical objects, without actually knocking them back?