Hello pilots,

Some how I am not able to change any settings on MCDU in the options for units, IRS align time, etc...
If I change units from LBS to KG for example, execute button lights on, but nothing actually happens when I press it. And if I go to other page, I can see immediately on the fuel gauges, that it changes back to LBS. One way I found to keep it in desired selection is to do that on the right side MCDU, but then it needs to stay on the same page entire flight. So it looks like save function is not working properly. Some kind of bug, bad installation or my mistake?
Will be grateful for any advice!

Regards, Viktor.