We both played malwing while his malwing had used bowback and mine was left in the field when his malwing entered for the second time he entered and sleept himself.
I was winning the battle regardless of the bug, and my team were fully posioned so the sleep wount affect me.
Just saw this Malwing bug myself (or maybe a different one). It was in Biweekly mission column 4, row 1. The enemy Malwing entered doing the stun and dreamy entrance on my team as usual. The next monster to get a turn was the enemy Kuraokami which used Snowslide but it weirdly hit the two Yuki on the enemy side of the field rather than my monsters.
There must be some bug in the latest update which is causing one of the next attacks/targets to flip onto the other team some of the time.