Hyper-V 2012 R2 issue on the 2nd vNIC in every VM

Dear Community,

for almost 4 month we have a problem on all our 2nd vNIC in every VM of our Hyper-V host.
When during a certain among of time there's no connection on the 2nd vNIC, we are receiving a Timeout, if we are using a ping or if we request the hosted website. We try 2 or 3 times and the connection works again. We suspect the lastest update of the Integration Services is causing these troubles , but we aren't really sure. We haven't found any clue in all the log files. It seems that the 2nd vNIC is sleeping (idle) and need lot of time to awake.

It's only the 2nd vNIC. 

It will be really nice if you can help us.

PS: as Hardware NIC we have some Intel I350 in teaming modus.

Regards,

Joel.