i just rectified this map from wikimedia commons:
https://commons.wikimedia.org/wiki/File:Sanborn_Fire_Insurance_Map_from_Rome,_Oneida_County,_New_York._LOC_sanborn06220_003-19.jpg
after rectification, the overlay did not appear in map warper and was not served by the tile url in JOSM.
i reran the rectification and the overlay appeared. after some delay, i was able to clear the JOSM cache and see the tile.
this seems to be an intermittant problem with a workaround, but it is still irritating.
i just rectified this map from wikimedia commons:
https://commons.wikimedia.org/wiki/File:Sanborn_Fire_Insurance_Map_from_Rome,_Oneida_County,_New_York._LOC_sanborn06220_003-19.jpg
after rectification, the overlay did not appear in map warper and was not served by the tile url in JOSM.
i reran the rectification and the overlay appeared. after some delay, i was able to clear the JOSM cache and see the tile.
this seems to be an intermittant problem with a workaround, but it is still irritating.