I haven't seen this yet. Never used the app - I use the mobile site usually while logged in (but not always). Unfortunately a few features are missing (like being able to see all items for some reason by a specific seller) but otherwise it works well.

Is this you on X or did you link to a random post ?

It looks like Amazon is starting to hide some reviews to protect against data scraping bots, and in some cases it is affecting real (non-bot) customers.

Were you signed in when you got the message? All of the sorting / filtering / search options are showing up fine for me (as a signed in user).