Hi Mado,
There seems to be a bug with the breeding pen where's if you filter genes for offspring and select 'random from pitcher' or 'receiver' the resulting genes will simply become the gene 'attuned'. Doing this for more then one gene will simply result in multiple 'attuned' genes stacking.
Selecting 'Specific from pitcher' or ' receiver' resolves this but is more costly.
Will this be fixed in 0.4 update?
I am currently using the 0.3 public build

