8600 chassis and 8612xlrs modules

[vene]

Hi, a customer is facing a very strange behavior with some 10gb 8612xlrs boards : they are trying to connect some HP server chassis to 8600. If they insert the 8612xlrs board into 8600 chassis, with all XFPs and optical fiber already attached, the links are coming to up operational status very quickly. The problems are appearing if the fiber between 8600 and server is removed (by manually removing the patch cord or by a fiber cut) : the 8600 port needs a very extensive period of time to go in up state (sometimes, about 15 min).
They removed the XFP from 8600 and put it into an Ers5600 switch and the link became operational in a very short time (normal behavior).
Same issues appear if they are trying to create a link between 8600 and 5600. We conclude from all tests that the 8600 end of the link is causing troubles.
This behavior has been seen on all their 4 8612xlrs boards, from two different 8610 chassis. They are running 5.1.8.0 software release.

Anyone saw this abnormal behavior in their environment?