We released the new Android app version 2.3.2-Beta.
Please update your Nuki app and give us your feedback!
FYI:
Still no notifications on Android 9 (Pie) with 2.32beta.
(In detail: Android 9 / MI-UI 10.2.x / Xiaomi Pocophone)
As stated here [APP UPDATE: Nuki Android App 2.3.1-Beta]
At another device (Android 7.12 /Lineage) notifications are fine.
On MI9 i have to disable all Akku otimysations, inklusiv in Apps. Then notifications are ok.
You may consider revising the notifications in French, there are some issues, such as:
Porte d’entree
Quelquun a {0} la porte “{1}”.
So, while the door’s name is known (in bold in notification title), it is not used in the body ({1}). The action under {0} in your template is also missing.
Also, “Quelqunn” should be corrected into “Quelqu’un”.
I also saw notifications mixing in the same text “automatiquement” (automatically) and “manuellement” (manually): you should make up your mind, it can hardly be both at the same time, I think.
Maybe about time to review your testing in French 
The other notification in French to correct I mentioned above is the following:
Porte d’entrée
Quelquun a déverrouillé automatiquement “Porte d’entrée” manuellement.
Likewise, Quelquun should be corrected into Quelqu’un, and I think the automatiquement should be removed. The notification corresponds to a user opening the locked door from inside (turning the cylinder).
In IFTTT, it corresponds to Manually (Key/Knob), it seems.
Thanks to react, at least to let me know that you take it into account.
@Fred Thanks for your feedback. This is very much appreciated and we will try to improve our translation workflows!