I have got an answer from tom erbe about this problem:
i think i have found the problem which is causing this (it is causing max to want to redraw the gui repeatedly). oddly enough, this bug seems only to be triggered by max. this fix will be in next vst release, which is due out soon.
You know, I have had quite a lot of problems with various vsts in maxmsp. Interesting to learn about the quicktime problems. I have had very many plugins that worked fine in other hosts act incredibly funny and invariably spike the cpu up to 100%. Such a shame ;/