This bug has been reported often before. There appears to be a very basic indexing or thread display bug in the forum software that should be (repeatedly) brought to the attention of the developers/maintainers. It probably has to do with the logic used to create the message list which gets displayed for each/any particular thread - most likely the logic fails either where it selects the _first_ message for display OR where it determines the _last_ message for display. This type of error can be really hard to find/see because:
1) When one starts or stops a list one deals with a counter which might begin at either "0" or "1"; it varies with program design and can get very hard to keep track of "down the road". The programmer must decide whether to perform an action (in this case, list a msg) at the current point in the program _OR_ increment the counter and _then_ perform the action. It
can gets confusing which option is needed when the value of the counter is more than 2 or 3.
2) if this logic takes place in MORE THAN ONE PLACE in the program instructions, it becomes difficult to find all the places one has to apply a correction. This latter issue can be greatly improved by careful software design but when maintaining a large existing system one doesn't have the option to redesign the whole @*^#**() thing.
I am following this forum:
https://permies.com/t/32423/food-medicine/Food-Cure-documentary-cancer
When I received an email note about a new posting I copy/pasted the enclosed link to view the thread, opened a browser and viewed that thread. The last post talked about Ben Goldacre's comments about alt medicine vs. his comments on industrial medicine. I then logged on to ensure that my history would show that I had visited the thread and thus would continue to receive email notification when a new message was posted. On scrolling to the bottom of the thread I found the last message which I has just read was now missing and I can no longer view that message at the end of the thread.
This has been a consistent bug. It probably will require a lot of tedious time to fix it. I understand that - I spent 25 years in IT, 10 of them writing stuff like this and I know debugging can be a PITA. But it's an in-your-face hassle for all participants so I'm bumping it again here. I will try to enter the forum again as a "stranger" after I log out and see if I can view the last message; if I can do that I will edit this message and post message numbers. However, that really doesn't matter because the problem just bounces down to whatever message is "last" in the thread.
Rufus