After upgrading the BIOS to 0156 something is wrong at fan control in BIOS Menu.
If I change in "Configuration->Fan Control" the value for "Minimum Duty Cycle" for "Front Fan Header" it happens changed for the Rear Fan Header. If I change the value for Rear Fan Header the same thing happens for Front Fan Header.
We would like to inform that we tested with BIOS versions 0151,0155 and 0156 and we are not able to duplicate the issue in our demo systems. All front, back and rear fans work fine even when stopping them with a finger reason why we recommend to reset BIOS to its default settings and to perform BIOS recovery to version 0156 using F7 after loading BIOS defaults: