U2415 in calibrated "standard" mode is yellow next to U2414 in calibrated "sRGB" mode

I have U2415 and U2414 plugged into DisplayPorts of the same computer.

Both are in factory default settings, in the factory calibrated mode: "Standard" for U2415 and "sRGB" for U2414.

U2415 has distinct yellow tint compared toU2414 and to all other displays I have available.

I had to set U2415 to colour temperature 7500K to more or less match "sRGB" mode on U2414. Similar effect in "Custom" mode is achieved with RGB values set to around 92, 92, 100 on U2415. Seems that blue is too weak on U2415.

If both monitors are factory calibrated to sRGB why is there so big difference?

I've tried resetting monitors, replacing cables, changing ports without effect. Operating system is Windows 8.1, no color profiles are installed.

Both monitors are new, I bought them from resellers here in Poland.

Regards
Michał