How to report VST3 issues?

[pongasoft]

I tried loading my own (free and open source) vst plugin SAM-SPL 64 into the latest release of Reason 12.0 and it does not work: after loading a sample into the device none of the pads play any sound.

* Loading the VST2 version works fine (note that from an implementation point of view, the VST2 plugin is the VST3 plugin with a thin VST2 wrapper layer around, so in the end the VST3 code is the same)
* Loading the VST3 into Maschine 2 (which also added VST3 support not too long ago) works fine.

=> So clearly it is an issue with Reason implementation of VST3.

Is there a specific way/location to report this kind of issues?

Thanks