One thing that comes to mind is ddos-protection.
Could you check:
show ddos-protection protocols [icmp | bgp]show ddos-protection protocols statistics terseshow ddos-protection statistics
Just in case you see any violation or dropped packets.
May be looking at the logs as well for bgp teardown reasons or ddos.
Although Late, but this problem was caused by L2-loop in one of our ERP rings. this has also occured second time to one of other routers and we had to deploy VPLS loop prevention as the ERP terminates on VPLS instance on the MXs.
one helpful command was "show l2-learning mac-move-buffer". this shows the looping vlan and the instance it belongs.
when this loop happens the symptoms are many "ddos protocal violation" log messages.
one of the issues we were facing was eBGP sesions were flapping.
LOOPS are Bad!