Thanks for the detailed clarification, I draw the topology according to your description in the attachment.
As I have said, I suspect that there are 2 LSP path in the mpls network.
When ping from remote site to Nexus VLAN, mpls network chose one EC...
There maybe more than one LSP in the mpls core network, when the remote site access nexus 192.168.30.1 on one LSP path which did no lose packet. And it lost packet on the other LSP path when access public Internet.
To narrow down the issue scope, I advise that one loopback interface be created on Nexus with IP like 192.168.10.x/32 (not used by any host ). Then ping 8.8.8.8 source loopback on Nexus to see if any packet loss.
