Hi
This is not a bug.
NCH say it's a behaviour difference between versions and is there for testing feedback) in the version you have a clip dropped manually onto the timeline overwrites the existing clip. IMHO ALL clips dropped to the timeline should insert themselves and there should be no overwriting.
To explain. When you install VP from the setup.exe file, you actually install a "version" of the program. It could be the A version; the B version etc.(It seems to be pot luck which installs.) Each version is complete but some features behave differently. In your version you have installed a version where dragging/ dropping clips directly on the timeline cause an overwrite and not an insert. The idea behind A/B testing is for users to give feedback on options they don't think are working in the expected way (like you have done here) The vertical or horizontal split popup that appears next to the red cursor line is an example, or the "hamburger" File button another.
Try this......
Without anything - no uninstall or anything- simply double click the setup.exe file again. This action will overwrite your "version" of VP with another. You may have to do this several times if the "version" that comes up displays the same behaviour.
As an example.
My original install of VP 8.20 did not insert clips, it annoying overwrote existing clips, but re-running the setup file a second time produced a "version" of 8.20 that did insert correctly.
The A/B idea can cause some confusion as support users can find their versions different to each other. Borate's version inserted clips OK, whilst mine didn't, so interpreting a users problem was awkward.
Nat