Mastervolt IVO Compact 12/25-3 charging problem

[Kinperi]

Hi, problem with Mastervolt IVO Copmact 12/25-3 charger.
Doesn't charge if it is connected to battery.
When multi-meter connected, voltage goes from 12V up to 19V.
Tested with flood option as well, same problem.
Any thoughts?

Regards,
Petri