Nah, it's not that it hasn't updated - did you not read the post?
They said that they were given a new discover weekly consisting of 30 songs they had heard before, or songs that had previously been in their discover weekly. They also explained that the total number of new songs (so, songs they haven't heard before) in each discover weekly was about 5-10, whereas the rest of the songs are duplicates from weeks gone by.
Just so you know, this is an ongoing problem that Spotify has refused to solve for years. The problem is that listening history is only rolled back 6 months, after which the algorithm used by spotify to pick "new songs" stops looking. So any songs you have not listened to in 6 months becomes fair game, which is asinine.
This is also not a new idea
I have a bug report about it here: https://community.spotify.com/t5/Other-Podcasts-Partners-etc/Discover-Bug-Songs-consistently-re-appe...
And there's an egregiously labelled "implemented idea" here:
https://community.spotify.com/t5/Implemented-Ideas/Discover-Weekly-Prevent-Duplicates-in-Discover-We...
I don't know why you are recommending to reinstall thee app, or clear the cache. Spotify's discover weekly is handed out on a user-to-user basis, you should be able to get your music from the web player alone if you so wish. This advice is a red herring, stop pretending like it does anything relating to your discover weekly.
It's not a hard thing to fix either - you already have the users complete listening history, list comparison between generated songs and the users listening history is not a difficult operation to perform.
Here's proof of it happening too: I've had this song called Shiki no uta in my discover weekly 4 times in the past 2 years

And also this song called Go Go Go (3 times )

And also this song (4 times)

TLDR:
Discover weekly does not respect the users listening history, and keeps giving back the same songs year after year