Audio hickups with Soundtoys plugins, please help.

[vanhaze]

Dear Reapers,

Situation:

MacPro 16 gig ram, year 2012.
Reaper latest version (64bit) , OSX 10.9.2 , MOTU 2408 MKIII, Buffersize: 512, Fs = 44.1 Khz, 16 bit.
MOTU Latest driver.
Soundtoys native fx, Radiator and Devil Loc, latest versions (64bit).

Whenever i insert a plugin from Soundtoys on a track and go in play, the sound has occasional hickups and audio crackling.
Seems to occur often when in Loop mode and the play cursor skips to the beginning of the loop.

When i look at the Performance meter in Reaper, there is barely any load.

So may i ask what the problem could be ?
I am aware of all the settings you can play with concerning (plugin) performance but really, this is all abacadabra for me.

I hope to get an answer with some kind of simple setting i can make to fix this problem :0)

Thanx in advance,

Robbie

[vanhaze]

Did some further testing ;
Seems for me the problem only occurs with the Audio Unit version, not the VST version.

[vanhaze]

More further testing:

Seems that alot of my vsti plugins give crackles when loop is on and the play cursor skips to the beginning of the loop.
When that skip occurs, also some audio crackling occurs.