Why does arbitration lockout happen when multiple Avalon-MM masters are connected to the tristate conduit pin sharer in Qsys?

If you have multiple Avalon Memory-Mapped (Avalon-MM) masters connected to multiple Avalon-MM generic tristate controllers which share a tristate conduit pin sharer, you might see arbitration lock-out happen. Arbitration is always granted to one active master, while locking up the other master's access to the pin sharer. This happens because the pin sharer always grants access to the master that heavily requests access.

Choose a non zero value for Qsys interconnect pipeline stages in \'Limit interconnect pipeline stages to\' field of Project Settings tab in Qsys.
This problem is scheduled to be fixed in a future release of the Quartus II software.