Timeline blocks additive animations from playing?

Hello,
I'm using the the timeline to create cut scenes and I need to play a talking animation while the other timeline animations are playing. I'm using a script to trigger an animation event whenever a gameobject is activated in the timeline. This approach works fine when an animation isn't playing, but when an animation is playing the talk animation will not show up.

Basically, how do I get an additive animation to play while another animation is active in the timeline? I know I can create an override track or another animation track and both animations will play, but I need to trigger the talk animation through a script for lip syncing the dialogue I cannot add the talk animation to the timeline itself.

I've attached a very simple example scene to this thread so it's the best way to understand the problem I'm having.



If you export the unitypackage you'll see the left character talks but the right one doesn't because it's attached to a timeline. You can mute the timeline animation track and you'll see that both characters talk, meaning the problem is definitely caused by the Idle animation playing. I just need some way to trigger the talk animation through code while the idle animation is playing.

Can anyone/a Unity employee take a quick look at the unitypackage I've attached?

Having characters that talk when the timeline is playing is a huge aspect of my game so I'd like to figure this out somehow. And I've looked at the other threads on this so don't just link another thread, they don't address the specific problem I'm having of trying to trigger an additive animation through code while the timeline animations are playing. Or if there's another way to do this then let me know too.

Any help is appreciated.