I actually stopped using instant shield on my Mecha when another monster is at 2 tu because of this. Only use it if they are on 3tu.
It’s not always like this though. According to the Devs it’s a 50% chance of happening in these situations.
Instant move is 1 tu
Enemy Monster is 2 tu
Instant move takes 1 second therefore both monsters are now on a tie break. The winner of the tie break is decided through RNG
50/50
Sometimes my mecha has kept it’s turn other times it hasn’t. I just don’t risk it anymore.
Please see the Devs reply to my post when I complained about this: