blue2000 -- thanks. Your experience seemingly differs from mine. I've done a quick survey, and found that for me, working on my own computer in my home, the following sub-forums "cut out half-way through", as described in my post of Sep. 3rd : Family and Children, Life In General, All In a Day's Work, Time For a Coffee Break, Entertainment and News, and the "crafting" sub-forum (forget its precise name). Others seemingly do not -- they're accessible throughout.
There appears to be a tendency by which sub-forums with a large number of pages, cut out half-way through for me; and those with a relatively small number of pages, don't. This is not universal, though: Entertainment and Hospitality, with many pages, seems accessible throughout; the "crafting" sub-forum, with only 21 pages, cuts out half-way through.
Computers are strange -- particularly for people like me, for whom the whole thing is mostly Harry Potter and bewildering magic. Further research by me into this issue, would seem to involve going to a public-use computer and seeing what happens there; and / or calling in relatives / friends more computer-savvy than I am, and asking for their opinion and advice on how I might get at what I at present can't get at. Frustratingly, all the sub-forums which I like most and frequent most, are among those where cutting out half-way through, is happening...