This applies to VMS17 Plat and VMS16 Plat. It may also affect earlier versions. To me it's a nasty bug, but if by design it's strange unexpected behaviour.
To illustrate here is an example timeline
With Rippling On (All tracks etc) delete the red item, and the following is what I expect with the yellow item moving along to fill in the gap area as vacated by the red item
But instead you get the following where the green item moves right along to meet the blue, and the second yellow and grey now sit on top of the white and first yellow
It appears VMS ignores that there are Events on the lower track? It caused me a timeline mess this afternoon!