CRS125 + Cisco 2960 trunk line went down and disabled ports

Hello Folks!

I face a problem…

I did upgrade from RB333 to CCR and in same time I did move from cisco 2960.
All update went very well, our internet become at least 3 times as fast as before.
Internet is still connected to a 100mbit/s port at cisco 2960.
From 2960 goes a gigabit trunk Gi0/2 ↔ eth1 to CRS125, where the CCR is connected.

Suddenly we lost contact to half our network and internet.
Gi0/2 lamp in Cisco was off and eth1 in CRS was off.
In Cisco logs there was a lot of issues about illegal/unexpected/unsupported vlans.
I can not tell which came first and what happened. I do not think Cisco can shut off eth1 in CRS, it does not support spanning tree as far I know.
I restarted the Cisco 2960, no difference.
I did rollback to RB333, then internet came up since it is connected to Cisco device.
I restarted CRS125 no difference, still no green ports.
I then moved the cable to eth24 (also trunk port in CRS), then both lamps become green again.

I then login to CRS using serial console port, then I saw X on eth1, it had become disabled by itself.!?.
I did simply enable eth1 again, moved back the cable, and stopped RB333 and started CCR, then green lights on eth1 and gi0/2 and all was ok again.

Looking in CRS on the eth1 port, I did not see any link down or other error neither in the logs, so it must have been disabled before Cisco started to complain.

Now I am scared that it should happen again, I let it run over the night and see if all goes well.

So how does CRS disable its ethernet ports by itself, anyone who knows ?

Problem was solved, we did investigate further, it was a human mistake after all, we did by mistake disable ether1 on CRS switch during changes in the CCR where we disabled ether1. That explains why there was no link down.