amber summit
Reproduction Steps: Kill monster during or right before an attack, stand still (or just don't move out of the attack's path)
Repro Rate: Seemingly 100% of the time following the above steps
Game Platform: Steam (Steam Deck)
Game Version: Latest
Wanted to add some additional details that may be helpful regarding this issue. It seems that all monsters can be affected by this issue, but certain ones are more likely due to the nature of their attack. Basically, if a monster is slain during its attack animation OR during the wind-up to the attack, the attack will happen. Certain monsters – especially the bat dude, armulite, and amalo, though sphekter is up there, too – have drawn out wind ups to their attack, drawn out attack animations, or drawn out death animations, and this seems to make them the most commonly affected by the issue. Armulite is by far the most notorious, which I think is a combination of its very long death animation and its very long attack. Sometimes, the white line showing where the attack will hit appears right as they are being slain, and while their model disappears before the attack is executed, the attack continues.
With armulite in particular, I've also noticed that I often take damage during the "white line" stage (before it turns to red, when their attack is actually in effect), but I think that this is a separate issue, because (1) it seems to only apply to armulite, whereas the attacking after death affects every monster to some extent, and (2) I experienced this issue before the latest update as well.
hard yew
strong reef
blissful echo
little solar
raw summit