Failing Twitter Embeds.

My twitter embeds are randomly failing. The symptoms are these:-
1. I edit a post.
2. Sometimes it works, sometimes it does not.
3. I edit it again, make absolutely no changes, and it either breaks or starts working.
4. It breaks far more often than it works (probably 90%). When it “breaks” the link, which should be the embedded tweet, is clickable – but it completely destroys the visual aspect of the site.
This is insanely frustrating and has been bugging me for well over a week – I’ve searched extensively but cannot find any actual solutions.
Please note there is no plugin installed for tweet processing, since with 3.4 it is now native.
An example “failed” post is:-
http://cgayling.com/malmaxa/2012/01/tweets-for-posterity-16/
An example “working post” is:-
http://cgayling.com/malmaxa/2012/01/tweets-for-posterity-15/
an example of the embed that will fail is:-

[embed]https://twitter.com/cgayling/status/262388268908306432[/embed]
<h6>A terrible thing about fame, is how often arrogance accompanies its arrival.</h6>
[embed]https://twitter.com/cgayling/status/262667323578658816[/embed]
<h6>Change, the catalyst.</h6>

Could this possibly be a caching issues, where the sites internal cache is somehow getting corrupted? I would be extremely grateful for any solutions, hopefully with an explanation as to why this is happening.