Hummingbird cache bug

Hi,
The last version of HummingBird is crashing several (but not all) of my sites. It seems that the css is not loaded anymore so the site looks all weird, I have tried several things (purging browser's cache, tryed brand new browser, empty server's cache, etc...) the only thing working is deactivating Hummingbird and everything fallback in place, if re-enabling hummingbird it goes weird again. As I said earlier the problem is occurring on several but not all sites, I didn't find any common denominator as to why those sites and not the others...
Please help, I like Hummingbird a lot and would like to re-enable it as soon as possible.

Thanks
Didier SZYLOWICZ