Why is my animation playing in Matinee but not PIE?

Reminder: I am working on a complex cut-scene comprising of ~50 imported FBX animations and currently featuring over 12 different camera placements and movements. Two of my FBX animations don’t work. But, oddly enough, exclusively outside of Matinee: they don’t work in PIE, or Matinee video export, but work well when trying them by playing with the trackline or playing in Matinee, or in asset preview.

First is a character and because of incredibly strict NDA I can’t show neither name, picture or anything about it. Its first animation is at fault here and the weirdest part is that it used to work until fairly recently. I have absolutely no idea what change could have caused it to stop working, as nothing changed it directly in a while.

I did notice however that if I forced Start position on my Matinee actor in the scene to approximately the time when my character should be visible, its animation did start correctly.

Second is a camera, the only one whose animation comes from an FBX file. So there’s a skeletal mesh of a cone with the animation, and a camera is childened to it. That’s the setup for which I have given a Matinee screenshot. In this case my Director cuts to the appropriate camera without problem, but the container’s animation never plays out.

For whatever reason, this doesn’t appear to be fixed by forcing start position to either the beginning or the middle of this animation: it just never works. Except when trying it out that is.

I end up with the double problem that I stuff doesn’t work, but worse than that I can’t even find a way to observe the faulty behaviour, as everything works as expected in “debug” setups.

I really need an answer from someone knowledgeable on this. I couldn’t find any related problem, let alone one that was answered. Nobody around me has any clue about this or time to dig much. Deadline is approaching fast and re-making my Matinee would take too much time for unguaranteed results.