Reuse of REF Cursor

Has anybody faced a problem with reusing a ref cursor?

C1 refcursor;
....
stmt := 'select1 ' ;
open C1 for execute stmt;
fetch C1 into rc1;
close C1;

stmt := 'select2 ...' ;
open C1 for execute stmt;
fetch C1 into rc2;
close C1;

???

I am getting inconsistent errors: IDTCONTEXT: PL/pgSQL function ...... ) line 42 at FETCH

PG Version 9.5.5 on Linux.

Thanks

Danny