I appear to be having this same issue in TB version 2.0.0.19 (20090105) and Lightning 0.9.
I am using one IMAPS server and one CalDAVS calendar. On start-up TB goes to 100% CPU and has no network capabilities. If I remove the CalDAVS calendar and restart TB seems to work again.
So, from my perspective, it appears that Lightning doesn't work with CalDAV as it renders TB useless. I do not have non SSL calendar sources available so I wouldn't know that Lightning worked with non-SSL CalDAV.
I appear to be having this same issue in TB version 2.0.0.19 (20090105) and Lightning 0.9.
I am using one IMAPS server and one CalDAVS calendar. On start-up TB goes to 100% CPU and has no network capabilities. If I remove the CalDAVS calendar and restart TB seems to work again.
So, from my perspective, it appears that Lightning doesn't work with CalDAV as it renders TB useless. I do not have non SSL calendar sources available so I wouldn't know that Lightning worked with non-SSL CalDAV.