So I just touched the wet paint, on a 2012 MacBookPro, Mojave, Logic 10.5.1 and got the 735 dB spike with a hefty click in the (turned down) internal speakers, but only when initially putting the VocalTransformer into a channelstrip with active audio. I could then move it around the slots with no issues, and deleting and re-instantiating did not produce a spike. If I quit Logic and re-do the sequence, it happens again, as before, only once.
Almost same setup here, but couldn't reproduce, Mojave and 10.5.1 too... Tried with audio and SWI tracks, gui open or closed, mono and stereo... Care to share a step by step to recreate ?
Logic Pro 10.5.1 • OS X 10.14.6 • MBP 15" Early 2013 • 2.4 GHz Intel Core i7 • 8GB RAM • iMac 27 Late 2013 • 3.4 GHz Intel Core i5 • 16GB RAM • Focusrite Saffire 6 USB • Presonus Inspire 1394 • Roland UM-One mkII • Behringer FCB1010 • Gibson ES335 • cheap midi keyboard