Hi Matthias,
this is a rounding issue.
When you set the format of this axis to at least 1 decimal, you will see, that the numbers will be
2,0 --> 2
1,5 --> 2
1,0 --> 1
0,5 --> 1
So far I did not find a possibility to set the formatting dynamically (via script).
We currently have some requirement to change formatting depending on the values. (high numbers without decimals, small numbers with 1 or even 2 decimals)
Depending on your local settings you might have problems to set correct '.' and ',' when you fix the formatting! (different notation for e.g. german and englisch)
Regards
Steve