Zorak

Some previous discussion is embedded in the infinite scroll thread:

Infinite / Automatic Scroll: issues, q&a, disable on desktop version

but IMO this issue warrants its own thread, and I didn't manage to locate one on a quick search, so starting a new one...

(further previous discussion available at the above link)

Although the problem has always been somewhat variable in nature (and I recognize that makes it hard to troubleshoot), it has been noticeably worse (for me anyway) in the last 5-7 days, happening a *lot*, and in some cases requiring opening the same thread 3-4 times to properly set the last-read marker, even though I am infinite-scrolling to the very end of the page, waiting a number of seconds (just in case the "update-last-read-marker" operation is one of the last things the forum code does), etc.

IBJoel

If you can get me a thread where this is happening to you (as well as browser and mobile/desktop skin), I can try troubleshooting more

Zorak

The problem of not correctly recording the last-read message only seems to happen on the mobile skin. i.e. if I last visited a thread in mobile, the next time I go back (whether the next visit is mobile or desktop) often I find it did not correctly record that I already saw those messages and it shows me a bunch again.

​​​​​​ On the other hand if my last visit to a thread was on desktop, I have never noticed a problem where the next subsequent visit to that thread starts from the "wrong" message.
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There is no one thread to give you -- this happens widely across all threads and all forums that I follow on FT. So I don't think it's like a database issue where a particular thread gets messed up (as sometimes happens following a merge)

All I can say is, if you use mobile skin with any frequency, and your primary method of reading FT is by following subscribed threads, you will notice this issue. My starting point on mobile is usually: https://www.flyertalk.com/forum/subs...n&folderid=all

Zorak

To elaborate, I usually read FT on my phone by opening the above link, and clicking the message counts with red dots on bolded threads that indicate there are new posts to read.

And often*, even after reading to the last post on such a thread, returning to the above linked page still shows the same thread as having new messages, even there there really aren't any. And it's not an issue with the summary page being cached, force-refresh of the page still shows the same thing.

*But not always, so as above, I realize that if it's not 100% reproducible then it's harder to troubleshoot. But someone with access to the code could maybe step through in debug mode and take a better guess where things are going wrong.

alex67500

Thanks for bumping this. I've taken the habit of refreshing each thread when I reach the last post to avoid it, but it's not ideal. I don't want to harass the admins either, it's annoying but not life threatening.

IBJoel For me it happens in absolutely every single thread to which I'm subscribed, on mobile and desktop (using Chrome), so take your pick.

Zorak

guess I'll count my blessings that this only seems to affect me on mobile, and intermittently at random!

​​​​​​BTW I omitted from my earlier replies the other info Joel requested -- I'm using Opera on Android.

plunet

I can confirm this, and I am sure IBJoel previously confirmed he had replicated the issue in the other thread. It happens when the number of unread new posts in a thread means you scroll across a virtual page boundary, whatever your page boundary is set to, the default and mine is 15.

Requires: use of mobile experience

• You read a thread youhave not read before. For example, it might have 10 posts in it. You read all of them. You leave the site and do something else.
• Later you return. The thread shows unread posts. There are now 19 posts (across a virtual page boundary of 15), so 9 new.
• Enter the thread to view new posts. You jump to post 11 as expected. You scroll down and read all the unread posts crossing the virtual page boundary of post 15/16, all the way to post 19.
• You leave the thread and go back to the forum. The thread shows there are still unread posts. [Face of disbelief]
• Enter the thread to view new posts. You now jump to post 16, ie. the first post in the virtual page after the one you last entered when reading the thread.
• If you now leave the thread it will show no unread posts. This is assuming the place where you enter the thread on this occasion is the last virtual page with 'unread' posts.

Of note:

• If there multiple virtual pages with unread messages you would either have to enter the thread multiple subsequent times to go to post 16, 31, 46, 61 etc. (assuming a virtual page size of 15)
• Or you can hit the >> symbol at the bottom of the thread to forceably jump into the last page of the thread to reset the last read counter correctly before leaving the thread

This is very very repeatable. And discussed last year Infinite / Automatic Scroll: issues, q&a, disable on desktop version around post 360ish