Autopilot Bug C-160 Transall? How to fix?

I mean that one when you select VS (in my case 1500ft/min), engage the AP and it completely went wrong and VS will be set to 14000(!!!)ft/min which leads very fast to stall. Or is it a bug you cannot fix and and a patch will fix it someday in future?

Duplicate of AP Alt issues with Transall C-160?