While converting from one geosystem to another polygons crossed by 180 meridian left got split into eastern and western parts. Tool used - ogr2ogr library.

Initial geosystem - WGS84, target - Albers-Siberia. Desired projection is shifted from Greenwich to the center of Siberia. So splitting each Chukotka region polygons (the far eastern ones in Eurasia) by two is needless. But conversion doesn't eliminate this artifact.

Is there a way to fix the problem?