The problem was caused - at least, in that post I linked - by an error in the use of the [url] tags.
You had:
Code:
See [url=http://www.ukba.homeoffice.gov.uk/business-sponsors/points/quick-guide-pbs/[/url]
but it should have been:
Code:
See [url=http://www.ukba.homeoffice.gov.uk/business-sponsors/points/quick-guide-pbs/]click here[/url]
Notice where I've added a closing bracket and the text "click here" before the closing [url] tag.
The general format of the named link url tags should be a URL followed by the text which will display instead of the URL in the post and since that text wasn't provided, the whole thing fell apart.
This is possibly specific to that particular thread - I've seen other odd errors resulting in weirdly corrupted displays that were caused by... well, nothing obvious, really - but simply editing a post somewhere upthread, to change only its layout, fixed those problems
downthread.
On balance, the named link url code tags as implemented here aren't really worth the effort because they don't properly highlight the text as being a clickable link and while it's possible to fiddle about with other attributes to create that effect, it's easiest to simply plonk the URL as plaintext into the post exactly as it appears in a browser address bar because then, it is automatically underlined and made clickable with no further fiddling required.
For example:
http://www.wrongplanet.net
(just be careful to ensure there is a leading and trailing space on the URL string, otherwise it's likely to be treated as ordinary text and not made clickable)
I've now corrected your first post (linked above ) and removed the invisible ones.
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Giraffe: a ruminant with a view.