Instancing - make real and join - duplicates itself

I made object A where the instances will go, parented object B to it, and activated Instancing on Verts (under Properties > Object Properties).

The instances appear as desired. Then I did 'make instances real' (I get to that by searching). Then I chose all the created instances, and joined them (Ctrl + J). Call that object C.

When I do that, object B becomes the same as object C. It duplicates itself the same way. In fact, if I then go in and edit object C, object B changes in the same way. And vice versa.

For me, this is the best way to do this. It allows me to export the combined object as a glTF and also keep the template object for later reuse or modification.

• It looks like it is something about object B, the one that is being instanced. I am trying to sanitize it, but so far no luck. I tried copying the object, copying all the faces in edit mode and then separating them into a new object. It has no modifiers now, no constraints. – kim holder Feb 14 at 21:44
• Thanks for the formatting, @brockmann – kim holder Feb 14 at 22:20