NullPointerException when training with h2o's AutoML

Question

I've been using h2o for about 3 years and first time these kind of error happens to me. I can't share a reproducible example because I'm using sensitive data but the dataset contains about 20K observations, R version 4.0.2, macOS Catalina 10.15.6, latest stable version h20 3.30.1.3. Could you please help me understand the error? This is the result after a couple of minutes training models (53% done according to the progress bar):

java.lang.NullPointerException

java.lang.NullPointerException
    at hex.ModelMetrics.getMetricFromModelMetric(ModelMetrics.java:151)
    at ai.h2o.automl.leaderboard.Leaderboard.getMetrics(Leaderboard.java:558)
    at ai.h2o.automl.leaderboard.Leaderboard.updateModels(Leaderboard.java:422)
    at ai.h2o.automl.leaderboard.Leaderboard.lambda$addModels$0(Leaderboard.java:381)
    at ai.h2o.automl.leaderboard.Leaderboard.atomicUpdate(Leaderboard.java:442)
    at ai.h2o.automl.leaderboard.Leaderboard.addModels(Leaderboard.java:378)
    at ai.h2o.automl.leaderboard.Leaderboard.addModel(Leaderboard.java:459)
    at ai.h2o.automl.ModelingStepsExecutor.addModel(ModelingStepsExecutor.java:186)
    at ai.h2o.automl.ModelingStepsExecutor.monitor(ModelingStepsExecutor.java:163)
    at ai.h2o.automl.ModelingStepsExecutor.submit(ModelingStepsExecutor.java:82)
    at ai.h2o.automl.AutoML.learn(AutoML.java:604)
    at ai.h2o.automl.AutoML.run(AutoML.java:407)
    at ai.h2o.automl.H2OJob$1.compute2(H2OJob.java:33)
    at water.H2O$H2OCountedCompleter.compute(H2O.java:1563)
    at jsr166y.CountedCompleter.exec(CountedCompleter.java:468)
    at jsr166y.ForkJoinTask.doExec(ForkJoinTask.java:263)
    at jsr166y.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:974)
    at jsr166y.ForkJoinPool.runWorker(ForkJoinPool.java:1477)
    at jsr166y.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:104)

I have a hunch that if I use the same data input for training_frame and leaderboard_frame this error happens. If there's anything else I can share to help understand this issue, let me know! Thanks.