I've had this problem since Sept, and there's a GitHub issue reported, if you want to add to it.
The bottom Nav inbox is the only one that seems to work right. Same with the inbox reply badge (telling you how many msgs are in your inbox.)
Device information
Sync version: v23.11.29-22:27
Sync flavor: googlePlay
Ultra user: false
View type: Compact
Push enabled: false
Device: bluejay
Model: Google Pixel 6a
Android: 13
Edit to add: it happens for me with left drawer nav and the one in the More Actions area of the top. Only Bottom Nav inbox works right for me