UPDATE 6/29/2011: If you run sa-update now, it should pick up 1140482 or later and fix this issue.
Due to a bug in the rule auto-promotion system, SEM rules were again mistakenly pushed to the active rules, causing a flood of unexpected DNS queries to this service provider. A very similar issue happened back in March 2011. Upstream spamassassin needs to make an emergency sa-update rule update to correct this situation. Meanwhile, all spamassassin admins should mitigate this issue by adding the following workaround to their local.cf then restarting their spamd.
score T_URIBL_SEM_FRESH_10 0