Stereo Tool

Hello
I am experiencing an issue with Stereo Tool.
Our radio station uses Myriad Playout (with presenters live remotely) and we use Stereo Tool for processing.
We use Stereo Tool with 2 input:
- the music, coming from the layout system
- the voice from the presenter, remote, via virtual audio cable.

I'm not an expert so I'm using basically the default setup on stereo tool.
However I have noticed 2 issues:
- The voice of the presenter gets broadcasted a lot later than when the presenter starts to talk, and feels like they're talking way after the songs are ended, leaving silence.
- When the presenter talks over the start of a song, the song starts low in volume (as Myriad Playout has a button ducking the music by a certain percentage), but then the music is pushed back up in volume after a few seconds, overpowering the voice of the presenter themselves, despite the ducking on our playout is still active.

Does anyone know what this could be due to?
I have uploaded a little snippet in mp3 if you want to hear what I'm talking about: https://we.tl/t-Hjxu6to4ZU

Thank you!