Why does this change?

[Lynne]

Well, it sounds like some sort of "str_replace" is going on, so I'd search for that term. However, they could also use "str_ireplace", so maybe search for "replace". This is just if you have a plugin doing this. But, some developers put the code in a script and call the script in the plugin. So, you may have to extend your search to files also. So, maybe the best thing to do is to turn off all your plugins and see if that fixes the issue. Then turn them on one-by-one to see which one is the culprit.