Problem with HTML formatting from emailed requests

Some requests that are sent to the ServiceDesk cause the whole serviceDesk page to appear in different colours. Usually this manifests itself in the font colours or background colours changing for the whole screen when I click on certain requests (only those sent by email, not those created using the webform).

In addition, since a recent upgrade to 5008 I have noticed that some spaces between words go missing both in the original request and in our reply to the request. This happens quite consistently with emailed requests and is not down to the requester (or technician) mis-typing but I think it's a problem with the HTML formatting.

Please see attached image - it shows the font colors for links having changed to the browser default colours (blue and purple) and missing spaces between some of the words in the request. ("emaildetails"...."Areyou")

We are running servicedesk ver 5008.