CPU Particle emitter + Mesh data + collisions Not working with parented sockets?

Hello,

Simple setup here, I have a CPU mesh emitting particles which collide normally with world static objects even when i move it about in the editor (as expected). as soon as i parent the particle emitter to the socket of another moving object the particles collisions suddenly stop working altogether and they just fall through the ground.

Am i missing a step?

Thanks in advance!

nevermind turns out a bug in 4.12 the latest hotfix fixed it.