Also, I should probably add that I currently have the SOD_SP v1.15b plugin installed and the HD+ option enabled. As for artifacts, Zidar only has the Spyglass (this is visible at the end of the video).
A little earlier on the same map, during a battle with Korback, the same strange phenomenon was observed (he also had the Magic Resistance skill, and I initially thought that was the cause). In any case, this doesn't save the enemies from death, but it does lead to greater losses on my side. Due to various random factors, I had to replay both battles several times to achieve fewer losses.
(Василь Симоненко. Люди – прекрасні)