Hey Breakthrough,
Thats basically the same problem as we have with the Virus TI (and other VSTs which do run through a soundcard driver): https://forum.renoise.com/t/renoise-virus-ti-vst-problems/21442
Those VSTs require that their VSTs run buffered & in sync with the ASIO driver. Renoise splits down buffers to smaller segments with the static buffers option disabled. Same thing happens when automating the VST parameters in many other hosts.
Thats nothing we can quickly change/fix, but we’ve got a solution for this, so we’ll take care of this in future. I don’t think that its a good idea to let the user specify the buffer size manually. This should work out of the box and not only when setting up stuff here and there depending on what audio settings you use. Aka, Renoise should take care of this automatically and not the user…