I'm a big user of the Objects window in v92.2 to keep track of what context I'm in, which has led to me making more of an effort to give meaningful labels to objects and to place objects into meaningful groups.

However, under some conditions I have not identified, using drag and drop in the "Objects" window to move an object into a group may actually change the position of that object on the page. Is this a bug, or is there some situation under which someone finds this behavior desirable (changing only group membership alters object position)?

I haven't heard of such a bug. I would suggest just to pay close attention, and the next time you see this happening, share the SVG file with us, and tell us exactly what steps to take, to reproduce it.

Are you dragging and dropping only within the Objects dialog? Or are you dragging to and from the dialog, from and to the canvas?

I would guess that it's related to some of the transform attribute bugs that seem to be particularly stubborn to fix. But there's really no way to know, until we can see it in action - and have something to show developers via a bug report.

There is probably a transform attribute applied to a layer.

Working in the Objects panel can be tricky...

Layers in Inkscape are actually special groups, and groups can have transforms like any other objects. The objects panel allows switching a layer into a group behavior and vice-versa, so when one layer has a transform, moving objects in/out of the layer will likely cause them to move.

Edit/PS:
Using the XML editor can also allow a layer to be selected and transformed, with the same issues.

1) Note the transform applied to Layer2 in object mode.
2) Note there is no transform on the path objects.
3) Note the ellipse moves when moved between Layer1 and Layer2.

(also note there is a bug with multiple object entries in the xml)

Thanks! I will reach for the XML editor next time this happens and look around for transforms.