After offline discussion with Arne it turns out that SDK 13 actually fixes the alignment, it is broken in SDK 11 and 12, see:
Thus, upgrading to VST 3.6.13 SDK (build 81) is highly recommended 
Best,
Stefan
After offline discussion with Arne it turns out that SDK 13 actually fixes the alignment, it is broken in SDK 11 and 12, see:
Thus, upgrading to VST 3.6.13 SDK (build 81) is highly recommended
Best,
Stefan