Hi, Henrik

was indeed a "RTFM" issue ... ... and you were also right !

The result should be configured as left-justified if you are performing an 8-bit
conversion. It should be right-justified if more than 8-bit precision is required. This
is also a register setting and will be found in the datasheet section on the Analog
Converter (ADC).
manual p 116 ...

BTW, it looks to be what to do with other Pics too ...