The issue you're encountering is related to the fact that arduino objects are not serializable and cannot be passed directly to parallel workers because they cannot be saved to disk. When using parallel processing in MATLAB, each worker operates in its own separate process, and objects like arduino cannot be directly shared across these processes.
If your goal is to toggle each LED randomly and independently you could try just creating the random order of pins and delay times before entering the loop, and then just loop through them. In the code below, you would just replace the display commands with your function to toggle the specified pin on/off.
pins = "D" + (1:10)
randIdx = randperm(length(pins));
pauseTimes = rand([1 10]);
for ii = randIdx
disp(pins(ii))
disp(pauseTimes(ii))
end
