Oh no your polygons are invalid. It's ok you are still a good person.
Usually it because the lines self overlap.
Probably a result of drawing a polygon with your finger or tracking with the GPS.
This is fine on NRDS but it messes up arcgis integration and some queries.
The solution it to clean up the overlap
Sometimes they are really tiny and you have to look for them.
Edit polygon
Click map
Find the overlap
Shift click to delete the ovelaping nodes
Save
Confirm your polygon is valid
If its a really complicated polygon or does not work please contact us and we can help fix it support@nrds.io