Why does ADFS have too many SQL connections open?

I'm running ADFS 2.0 in Windows 2008r2, connected to a SQL Server 2005 database server. Right now the ADFS server has 5623 TCP connections open to the SQL server (checked via netstat - counted with powershell). This many connections is impacting our SQL server and preventing backups from running properly.

Going off of this question, it seems that ADFS may not be closing its SQL connections, however the connections are all in the "Established" state. This became an issue once before several months ago; if I recall correctly, I resolved it by resetting the NIC (to forcefully kill all active connections). This time around I'm looking at restarting the ADFS services first.

But the question is why is this happening in the first place, and how can I troubleshoot the root cause? I've done quite a bit of research and can't find anything that would point the finger at ADFS - such as a bug or something.