Oracle Spatial geometry transformation from one SRID to another and back doesn't result in same coordinates

Question

I am doing the following transformation from SRID 4326 to SRID 21781:

select SDO_CS.TRANSFORM(SDO_GEOMETRY(2001, 4326,SDO_POINT_TYPE(8.554697094, 47.355028826, NULL),NULL,NULL),21781) geometrie from dual;

Which results in the correct coordinates: 684237.530726634 / 245289.311003668

But when I transform this back to SRID 4326:

select SDO_CS.TRANSFORM(SDO_GEOMETRY(2001,21781,SDO_POINT_TYPE(684237.530726634, 245289.311003668, NULL),NULL,NULL),4326) geometrie from dual;

The resulting coordinates are completely wrong: 8.19567132311754 / 0.232474117334404

What am I doing wrong?

Answer 1

Updated to 11.2.0.2.0, now the result is correct. It is a bug in versions < 11.2.0.1.0.