NullPointerException when running Flink Nexmark tests on Streaming after switch to SDF based translation

When running Nexmark on Streaming mode with Flink locally via:
 
/gradlew :sdks:java:testing:nexmark:run \
      -Pnexmark.runner=":runners:flink:1.10" \
      -Pnexmark.args=" \
          --runner=FlinkRunner \
          --streaming=true \
          --suite=SMOKE \
          --manageResources=false \
          --monitorJobs=true \
          --enforceEncodability=true \
          --enforceImmutability=true"
 
I see the following error and get no results (this works ok in Beam 2.24.0)
 
Caused by: org.apache.beam.sdk.util.UserCodeException: java.lang.NullPointerException
        at org.apache.beam.sdk.util.UserCodeException.wrap(UserCodeException.java:36)
        at org.apache.beam.sdk.io.Read$UnboundedSourceAsSDFWrapperFn$DoFnInvoker.invokeNewWatermarkEstimator(Unknown Source)
        at org.apache.beam.runners.core.SplittableParDoViaKeyedWorkItems$ProcessFn.processElement(SplittableParDoViaKeyedWorkItems.java:439)
        at org.apache.beam.runners.core.SplittableParDoViaKeyedWorkItems$ProcessFn$DoFnInvoker.invokeProcessElement(Unknown Source)
        at org.apache.beam.runners.core.SimpleDoFnRunner.invokeProcessElement(SimpleDoFnRunner.java:227)
        at org.apache.beam.runners.core.SimpleDoFnRunner.processElement(SimpleDoFnRunner.java:183)
        at org.apache.beam.runners.flink.metrics.DoFnRunnerWithMetricsUpdate.processElement(DoFnRunnerWithMetricsUpdate.java:62)
        at org.apache.beam.runners.flink.translation.wrappers.streaming.SplittableDoFnOperator.fireTimer(SplittableDoFnOperator.java:171)
        at org.apache.beam.runners.flink.translation.wrappers.streaming.DoFnOperator$FlinkTimerInternals.processPendingProcessingTimeTimers(DoFnOperator.java:1317)
        at org.apache.beam.runners.flink.translation.wrappers.streaming.DoFnOperator.close(DoFnOperator.java:575)
        at org.apache.beam.runners.flink.translation.wrappers.streaming.SplittableDoFnOperator.close(SplittableDoFnOperator.java:179)
        at org.apache.flink.streaming.runtime.tasks.StreamTask.closeAllOperators(StreamTask.java:618)
        at org.apache.flink.streaming.runtime.tasks.StreamTask.lambda$afterInvoke$1(StreamTask.java:498)
        at org.apache.flink.streaming.runtime.tasks.StreamTaskActionExecutor$SynchronizedStreamTaskActionExecutor.runThrowing(StreamTaskActionExecutor.java:94)
        at org.apache.flink.streaming.runtime.tasks.StreamTask.afterInvoke(StreamTask.java:496)
        at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:477)
        at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:708)
        at org.apache.flink.runtime.taskmanager.Task.run(Task.java:533)
        at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException
        at org.apache.beam.sdk.io.Read$UnboundedSourceAsSDFWrapperFn.ensureTimestampWithinBounds(Read.java:541)
        at org.apache.beam.sdk.io.Read$UnboundedSourceAsSDFWrapperFn.newWatermarkEstimator(Read.java:552)