Hi Salk, really appreciate the issue report!
I am very intrigued by this behavior and was able to reproduce the issue with Horned Kath Hound, Katarrn, and droids in Marka Ragnos' tomb. However, when I tested it on other combat scenarios, the target only waits until the current round ends and proceeds to charge toward my party regardless of distance.
I'm convinced it's some hidden engine issue, when EffectForcePushed is used as a standalone effect, it does not signal the events properly, (shamelessly blame the engine for everything that's gone wrong🤣). Unfortunately, nwscript.nss' source code isn't available and there is no way I could pin down the very source of this issue. Nonetheless, if I append a very short stun effect after the knockdown, the issue went away (I retested all 3 scenarios to make sure). It becomes clear that when the stun effect is over, it resets/clears the object's state and signals events properly. Since the failure to resume attack only occurs on Human-Subrace-Beast and Droid, I added condition checks in the original script and applied a very short stun/droid-stun effect after the knockdown.
Dropping the attached ncs to your override should now fix the issue, I'll make an update shortly. Let me know if the issue persists, or if there are any other weird behaviors, thanks again!
fp_saberthrow.ncs