SmartThings Notifications not working on Kindle Fire 7 (9th Gen)

Hello all, I am using two Kindle Fire 7 tablets with ActionTiles as my KIOSKs for my home alarm. The new ST app requires the user to dismiss an intruder notification when the alarm in armed and a door/window is opened, in order to disable the siren. (Guess this is a feature… not a bug) The notification is a push notification that appears on all other android devices running ST, but for some reason I cannot get the push notification to pop-up on the Kindle Fire Tablets. This makes disarming my alarm using the KIOSKs pointless, since I still need to open ST and dismiss the intruder notification.

Anyone have any idea what I need to do in order to get these notifications on my Fire tablets?

Here’s my setup:

Kindle Fire 7 (9th Gen) with Google play services, play store etc. installed via the Fire Toolkit.
SmartThings app (New app not classic) with notifications on
Notifications are enabled in the Fire notification settings
One tablet has all the Amazon apps and services disabled, but the other one still has all that stuff just to rule out that being the issue.
The Fires do show other notifications in the notification bar.

Thanks in advance