There is both VST3 and VST 3.5
Do you have an example of any non-Steinberg host that can actually load VST3 plugins?
As the OpenMPT manual and various places on this website say: Like virtually all other VST hosts that are not by Steinberg, OpenMPT does not support VST3 and higher. Which is not much of a loss, given the little number of actual VST3 plugins...
FL Studio can load VST 3.1.0 plugins.
And there i can use melodyne to crash my DAW by copy something between different plugins and closing them afterwards with the content from the copy buffer in ram to then copy again in for example kontakt5 mapping editor. Instant crash to desktop.