Why is req.Plan.Get() in my Create() method throwing an error?

Terraform Providers Plugin Development
2

I realized I should have included the data structure I was trying to use as the plan:

type ResourceMyThing struct {    
        Name      types.String `tfsdk:"name"`
        NestedSet []NS         `tfsdk:"nested_set"`
}

type NS struct {
        Name              types.String `tfsdk:"name"`
        ProblemNestedList []PNL        `tfsdk:"problem_nested_list"`
}

type PNL struct {
        Attr1 types.Int64 `tfsdk:"attr_1"`
        Attr2 types.Int64 `tfsdk:"attr_2"`
}

Also, I suspect the fix I’m looking for is lurking in this issue, but I haven’t worked it out yet.