Hey there ,
I remember in Houdini 16 when TopoBuild/PolyDraw was just introduced there was an option not to weld points in "Build" mode by holding down Ctr key while dragging points around.
Starting version 17 there were new handle snapping introduced https://www.sidefx.com/docs/houdini/news/17/model.html#postmeta [www.sidefx.com]
Which is also mapped to Ctr key and looks like it overrides polydraw functionality.
I wonder was that feature mapped to another key or was it lost?
Was quite useful...