Key-frames added with a wrong value

During the workshops with a client we noticed, that adding keyframes using both methods: property editor (Add keyframe) and timeline editor (auto-key) ended with wrong values. 

As I could notice - only the first keyframe had proper value, the rest of the keyframes had the same value as the first one.

The only workaround was to change the values manually in code, in some cases it was possible to change the value by double-clicking on the keyframe and edditing the value.