Why can't I reduce the length of the selection range in WKWebView in Catalyst on macOS Sequoia?

If I have a Catalyst app with a WKWebView and I select text, I can drag forward to extend the selection, but I can't reduce the length of the selected range by dragging backwards. I've reproduced this in a trivial sample app.

Is there some property I need to set somewhere?

I've filed this as FB15645411.

Why can't I reduce the length of the selection range in WKWebView in Catalyst on macOS Sequoia?
 
 
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