Thanks for your patience while we were looking into this — we made an intentional change to the topic timeline on mobile to save space and reduce visual overwhelm that can negatively impact navigation and the user experience as a whole. We won’t be reverting that change at this time.
Our suggested workaround is to use the Mark unread button to return the topic to unread status, if you need to make sure it stays unread after changing the notification level. If you don’t see that button yet, you can update the Enable mark topics as unread setting in your interface preferences.
I understand this isn’t the news you wanted to hear. If you’d like to share more feedback with us, please open a Feature topic to explain your use case in more detail — this may help uncover an existing solution or help us plan future improvements.