BeepBoop vs Yatagan

I've noticed that versus Yatagan BeepBoop never moves. The bullet shielding is effective enough that BeepBoop wins comfortably but I'm curious whether this behaviour is a bug or not. So far I've not seen any other bots that BeepBoop responds to in this way.

A quick way to find these bots is to filter bots BeepBoop win at near 100% APS while they have quite high APS in average. Another quick way is to look at positive KNNPBI bots of BeepBoop.

Also BeepBoop is open source, so you can have a look at the white list of shieldable bots ;)

I thought it might be some kind of whitelist, I should probably have had a look for one. I wonder how much APS the whitelist is worth?

IIRC BeepBoop without shield should be near APS 92%+, so the shield whitelist worth 2%-3% APS. Given that it already has very high APS, the APS gain of the shield system should be must higher on bots with less APS.