Only a single member-level [RowCountHint(...)] can be specified (to allow a per-call estimated row count hint); remove the duplicate.

Bad:

[RowCountHint]
public int X {get;set;}

[RowCountHint]
public int Y {get;set;}

Good:

[RowCountHint]
public int X {get;set;}

public int Y {get;set;}