Iframe bug

Hi,
First of all I’m using your plugin since a while and it’s really usefull ! Thank you !
I just found an issue on some pages which are showing iframes (in fact nextgen gallery slider)… It seems that these iframes are loading the HEAD of the website with the .less files and not the compiled. This make a lot of 404 in the console error.
Do you know how I can prevent this ?
Sincerely, Boris

https://ww.wp.xz.cn/plugins/wp-less/