I have been able to reproduce this issue in the FourPaneViewer example (https://gitlab.kitware.com/vtk/vtk/-/tree/v9.3.0/Examples/GUI/Qt/FourPaneViewer)
If you have a distance widget added to a scene and have interacted with the handles, and then you zoom/pan, the handles do not change their position on the screen with the rest of the widget. Once you complete the action, the handles then snap to the correct position.
Interestingly, if you do a zoom/pan prior to interacting with the handles, they change their positions properly.
Has anyone else come across this issue or have any breadcrumbs to follow in fixing it? Seems like it may have been around for a while: [vtkusers] [vtkDistanceWidget] 2D point handle does not follow mouse interaction