Cisco QSFP+ DAC manufacturer specific problems

I was having a hell of a week trying to connect a Mellanox ConnectX-3 NIC to a Mikrotik CRS354 Switch, it was a no go until I changed the DAC for a CISCO-TYCO one, it was the same model (Cisco QSFP-H40G-CU5M), but the CISCO-JPC ones won't link no matter what, I've tried 4 of them to be sure

The cables work fine between 2 NICs or 2 switches but not between a NIC and a switch

Has anyone encountered such exoteric issue?