Map has been downloaded several times with updates since this first started happening.
No, closest owned land would be field 44 to the east, water to the west, field 30, start farm to the north, the strip of land to the south of field 41, 42, 43 etc to the south.
Playing around with it, approaching with this combination of harvester and header got the no access if from the west side as soon as the header reached the crop. Coming from the north, you could harvest it, as long as the header stayed within the field. Coming from the south and east it just got no access message.
Previous occasion was with a lemkin cultivator about 16m wide. It left a strip a bit wider than the harvester in the screenshot, and a bit of that could be worked from the west side.