A drop down list parameter in a substance that start with a 0 index when published and imported in marmoset will display all entries correctly but will internally shift the selection so there is no way of actually using the first entry.
0 | Label 1 < Selected
1 | Label 2 < Actually using
2 | Label 3
Drop down list that start with index 1 don't seem to have the same problem.
1 | Label 1 < Selected & actually using
2 | Label 2
3 | Label 3