GMS v115 bugs & glitches

I would doubt it's a typo. The mobID of Dark Wyvern is 8150302. The mobID of bacal is 9420923 / 9420924. Looking at the animation it would make sense that bacals are summoned and not dark wyverns, of which I see it only summons two of them. It seems fairly deliberate. I don't see a reason why it would glitch when you hit the Dark Wyverns. Those are the same mobIDs that are used for dark wyverns in all other non-boss maps.