The game added 2 new franchises to a standard MLB game in 2021 (San Antonio, Indianapolis), but most players drafted in the expansion draft were assigned to the Diamondbacks with seemingly no reason or history recorded. They all simply appeared in the D-Backs DFA list. The drafted players not given to Arizona seem to be mostly placed on the opposite expansion team to the one that drafted them.
Edit: Looking into this more it seems that it's not a draft bug, but the expansion teams seem to be affiliated to Arizona, I'm going to attach a screenshot but uploading the league file will take me few hours