Transparent Borgs.

[Clarks]

Pointblank tasing or batoning a borg will cause it to lose density for the rest of the round. Even after the borg recovers, it can be walked through and other players can be on its same tile.

[Convair880]

It's only part of the problem. From what I understand, pointblank shots will indeed or at least have a chance to trigger the "knockdown bug" and since cyborgs can't stand up again, they'll be able to move freely through other players as you noticed and any tool that doesn't work instantly (wrench, welding tool, syringe, etc.) will be rendered useless. I assume it breaks the affected suit permanently, because rewriting the module or using a docking station didn't solve the issue when my metal body was suffering from the effects.