[c-nsp] strange issue on mcast flow

[R LAS]

Hi,
I’ve tricky problem:

Net scenario
Multicast Provider --- link 1Gbs --- c6500 --- c3925 (NAT/ACL)  --- 1Gbs link --  customer

When my multicast provider have some spike I see a lot of input errors/overrun on C3925 and customer experience loss of mcast flow.

Then I tried to move the link directly in an interface of C3925 (doing NAT and ACL) bypassing C6500 and do not see anymore input errors/overrun

New Scenario
Multicast Provider --- link 1Gbs --- c3925 (NAT/ACL) --- --- 1Gbs link --  customer

Any idea why this could happens ?

Greetings