mask air only not working correctly

• effect:blockmask{m=light;oa=true;na=false;r=0.1;d=60;Shape=CUBE} @forward{f=1;y=1.2;lockpitch=true}
• effect:blockmask{m=light;oa=true;r=0.1;d=60;Shape=CUBE} @forward{f=1;y=1.2;lockpitch=true}

oa=true doesnt seem to work correctly, with these lines non air blocks also get masked, especially visible in water.

This also happens on the newest Dev version.