OK today morning I was in DC and I think for 99% it is the problem of optics.
I had only in stock a Cisco 1 GB SFP-SX transceiver modules, and the partner from which we bough Junipers told us the Cisco GBICs should work normally with QFX 5110.
Well, apparently is not 
I made a loop connection between two ports on Juniper (both Cisco GBIC) and ports stayed dead. So I assume Juniper doesnt like them. So the solution in my case would be to buy some GBICs Juniper coded.
Funny is that Cisco 10 GB SFP+ GBICs works fine. LOL !