2960X SFP port just goes down

[roger perkin]

I have a stack of 4 2960Xs connecting to a single 2960X via 2 fibres 

In Gi1/0/49 and 50 I have a GLC-SX-MM SFP 

Both ports are in an etherchannel using LACP 

Randomly one of the SFPs will shut down 

The only log message you get is int Gi1/0/49 has gone down.

the Laser goes out and the only way to restore the link is to re-seat the SFP

I have tried multiple SFPs all with the same behaviour 

There was a bug around this from a few years ago

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCur56395/?referring_site=bugquickviewredir

But the fix was to upgrade 

I am running 15.2(2)E5 

The behaviour happens if I am patched both fibres into the same switch or cross-stack

Anyone seen anything like this before or can help me troubleshoot it?

Thanks

Roger

[Reza Sharifi]

We had the same issue with 30 2960x brand new switches.  They would behave the same way when connecting to a set of 4500x VSS. We upgraded multiple times to the latest IOS version Cisco recommended with no luck.  We replaced all 2960s with 3650s and the problem went away.

HTH