Attempting to generate watermarks chained to the Split Reader / ContinuousFileReaderOperator, as in
leads to the Watermarks failing to be produced. Breaking the chain, via disableOperatorChaining() or a rebalance, works around the bug. Using punctuated watermarks also avoids the issue.
Looking at this in the debugger reveals that timer service is being prematurely quiesced.
In many respects this is
FLINK-7666 brought back to life.
The problem is not present in 1.9.3.
There's a minimal reproducible example in https://github.com/alpinegizmo/flink-question-001/tree/bug.