“arbitrary stop errors because of excess overlap” : Bugs : Enblend
Sometimes enblend stops with error code 1 and a message "excessive overlap detected; remove one of the images". This behavior is arbitrary. F.e. a test project with 8 images all in the exact same place on an equirectangular canvas doesn't cause the error.
via Bug #685893 (sf-2932316) “arbitrary stop errors because of exces...” : Bugs : Enblend.