I'm not sure if this is the same issue, but I did find a bug where the links were getting cut off, so that the "Linkout" displayed on the tooltip in the Large calendar would only display part of the url. It's in ec_js.php, around line 400 or so, there is a line that includes
substr($linkout,0,19)
which is retarded. No idea what it's doing there, taking only the first 19 characters of the url. But if you change that to just
$linkout
the full urls will be displayed.
Edit: by the way, this is in version 6.5.2.2, according to the readme.