Preview of advanced message entry lies

I just created this note: https://sprinter-source.com/forum/showpost.php?p=559934&postcount=1
...
now look at it with this link: https://sprinter-source.com/forum/showthread.php?p=559934#post559934

and the Preview did NOT reveal that the vimeo players were going to appear.
The preview just showed the links as (first one) a legible link
and (2nd one) showed the plain text of the message instead of the link that wraps it.

Even weirder: the link above *also* did not show the players.... it showed
-----start quote-------------
It would appear that the forum embeds a player window for vimeo addresses, similar to YouTube.

Example:

https://vimeo.com/217407298

or when the link tool is used around this text

Which was https://vimeo.com/217407298 in plain text.
---end quote-------------
...which is what the preview showed.
(the source code for "around this text" was [URL="https://vimeo.com/217407298"]around this text[/URL] )

When viewed as a thread, the players appear: https://sprinter-source.com/forum/showthread.php?p=559934#post559934

--dick
p.s. the players also disappear if i *edit* the post... the after-submit refresh shows only the text.
But if i simply reload that page (reload icon in FireFox), the players reappear
Reloading the "postcount=1" example does NOT reveal the players.

I have to look into the code since I don't have a quick answer. Been getting ready for a road trip and some windshield issue.

No problem, no rush... simply documenting it

have fun on the trip (bringing along your windshield squoosher?)
--dick

Just today it seems that the lower video advert box is able to jump my page to the bottom. When scrolled back up to where I like, it sometimes jumps back down.

Added:
Google Chrome.

vic