SBC trunk status change to down email notifications not received

[Wawa]

I have a self hosted cloud instance running v18.0 (Build 312) on lightsail. It had a raspberry pi SBC until recently. I had enabled email notifications for "When the status of a trunk / SBC changes".
I received emails any time the SBC lost or regained connectivity. This was wonderful.

I recently replaced the SBC and a phone with a router phone (Yealink T53W).
Calls and everything the users want work fine, but I only receive email notifications when the router phone/SBC regains connectivity (changes status to up).
I do not receive an email when it loses connectivity (changes status to down) anymore.

Anyone else seen this or have ideas on what's wrong?

 

[SweetAction]

Down notifications can take up to 30 seconds to trigger - up notifications can be less time.
In a situation where it goes down and up within 30 seconds you will only get up notifications without down. This is true of anything SBC, regardless of routerphone or not.