KiCAD: Weird ratsnest
In order for traces to connect to the zone, they need to have an endpoint inside the zone.  Here, you have a trace (the vertical Vdd) that begins and ends outside of the zone fill.
This is logged as https://gitlab.com/kicad/code/kicad/-/issues/1800 in the KiCad issue tracker.
Unfortunately, so far the fix for this will impose performance penalties too great to have it always enabled.  We are working toward a long-term fix that will be acceptable.