I tried to replicate this and I am not able.
Once I do "unconfigure slot" on my EXOS the followed rediscover does update the DeviceView Ports tab.
I can not tell if the issue is in XMC or in EXOS.
If the reboot of the XMC solves the issue then I guess the bug is in XMC.
If the reboot of the switch solves the issue then I guess the bug is in EXOS.
I suggest contacting GTAC if those products are under contract.