Cufon has a slight delay when refreshing BUT not when directly loading the page

I am using Cufon in Firefox, it has a slight delay of converting fonts to images when I F5 but not if I click on th开发者_StackOverflow中文版e URL bar and hit enter.

Any idea why? And it wasn't originally like this, I tried to add a line replacing another selector and then this happened. Then I undoed but the problem remains.

I assume this is because pressing F5 forces a reload of all attached scripts as well, which prolongs the time until the cufon replacement is processed (while the layout is already being rendered).

When entering a page normally, or reloading it by entering its URL again, the embedded scripts are not reloaded.