Correcting nature preserve boundaries

I am a GIS manager at a regional conservation nonprofit organization. We manage ~32 nature preserves and I’m currently working on updating our property boundary data for a couple of web apps. Some of our boundaries have been added in the past by users, but they do not align with our current data.

I have attempted deleting the boundaries, and the editable outline is gone, but a green polygon still appears in the OSM Standard basemap. I would like to have a fresh start to these maps with all of our updated data (our previous GIS person was more than a little disorganized and I have a lot of cleaning up to do). Any help is appreciated. Thanks!

It can take up to a few hours for some zoom levels to get re-rendered. If that is not the problem, you are going to have to identify the specific object. It looks like is one of the three.

In fact looking at this item, I do see that the only issue is the non-issue of lower zoom levels not having been re-rendered yet.

One other thing, in my view, delete and re-add is bad practice. You should edit the the existing object into the correct shape, instead.

Thanks for replying. I see that it changes based on zoom level so will wait it out and see.
And while I appreciate the notion of deleting and re-adding, these are only a few of our >30 preserves, and I need data to be consistent across multiple sites that use OSM, so I would really rather have a clean slate.

Using JOSM, if you have opened your new boundary in one layer (perhaps as a shapefile or json) and have the current osm data in another layer, you can select one of the correct boundaries and merge them in to the current osm layer. Then activate the osm data layer, select both the old incorrect boundary and the new correct boundary (that you have merged into this layer), then select ‘More Tools’ > ‘Replace Geometry’. This method will retain the history of the boundary.
It is best to Merge one area at a time and you must only select 2 boundaries when using ReplaceGeometry.
You will need to load the UtilsPlugin2 to use the ‘ReplaceGeometry’ tool.
**When uploading to OSM be careful that you have the osm data layer activated and not the shapefile or other type you have loaded in another layer. JOSM should give a warning if you try to upload the wrong one.

The reason we ask you to update the boundary is that we value our mappers a lot. A mapper rather sees her/his work improved than deleted and replaced. When you update boundary, you can see the history of all mappers that that worked on a boundary.
So it is mainly a question to honor the work of other mappers, rather than to annoy you (we realize it is more work for you)