Thanks for your response! Unfortunately, clearing the buffers before running the sketch does not solve the problem. However, initializing the array passed into sketch.js with all zeros does seem to ensure that the sketch does not load with Trill touch locations from the previous program run.
There are still 2 issues:
1) The GUI takes a very long time to load (and the timing is variable), even after starting auxiliary functions after setting up the GUI in render.cpp (and inserting a ~5s delay before setting up the GUI and calling auxiliary functions, per @giuliomoro's suggestion).
2) The mouseClicked() function in sketch.js occasionally registers a mouseClick when the program is started when there is no mouse click. I have a suspicion that this is a holdover from the previous program run. Do you have any suggestions for why this might occur?
Many thanks again!