DWG - Export - somes hatches appear as SOLID

When exporting to DWG some hatches are displayed as SOLID hatch. First I thought the export process is to blame or its due to the known issue with hatches and large coordinate values.

same hatch - different appearance

The funny thing was, that the properties of the hatch looked good - it got the right hatch pattern and scale assigned - but nonetheless appeared as "solid". Increasing the hatch scale helped to display the hatch correctly - but I didn't want to change the hatch scale.

It turns out that setting the AutoCAD variable HPMAXLINES to 10'000'000 solves the display issue.

increasing hpmaxlines solves the display issue

Map 2013, Sp2