Error with parallelized RL training with PPO

Hello,

At the end of my parallelized RL training, i am getting the following warning, which is then causing one of the parallel pool's workers to automatically shut down. Is there a known cause for this? It says it is an error inside of the "onCleanup" class, but i am not using any custom functions for this (it is the one already implemented in MATLAB).

It seems to be happening only for one worker for some reason, and no crash dump is being generated.

Warning: The following error was caught while executing 'onCleanup' class
destructor:
Error using rl.train.parallel.AbstractParallelTrainer/cleanupPostRun_
Invalid input for argument 2 (rhs2):
Value must be a scalar.

Error in rl.train.parallel.AbstractParallelTrainer>@()cleanupPostRun_(this)
(line 21)
cln1 = onCleanup(@() cleanupPostRun_(this));

Error in onCleanup/delete (line 25)
obj.task();

Error in rl.train.parallel.AbstractParallelTrainer/run (line 141)
end

Error in rl.train.TrainingManager/train (line 479)
run(trainer);

Error in rl.train.TrainingManager/run (line 233)
train(this);

Error in rl.agent.AbstractAgent/train (line 136)
trainingResult = run(trainMgr,checkpoint);

[Drew Davis]

Hi Matteo

Do you have reproduction steps you could share, specifically your MATLAB environment class?

Drew