I am not sure what the problem is but I have also experienced a crash of the host at one point because of an assert in the VSTGUI code. The point being that when it happened, there was a report on the cli where I had started my DAW so I knew what the problem was (in my case it was CControl::endEdit L154 => vstgui_assert(editing >= 0) and using a control that comes with the sdk not my own… so there is at a bug somewhere which triggers this assert if you click too fast…)
While developing I always start my DAW from the command line that way I get all my debugging/info statements and assert logs right in that window…
This is how I start the one I use (macOs): /Applications/Reason\ 9/Reason.app/Contents/MacOS/Reason
I know this isn’t a solution but it may give you some ideas on troubleshooting
Yan