## Known Caveats

*   TF Core:
    *   A longstanding bug in `tf.while_loop`, which caused it to execute
        sequentially, even when `parallel_iterations>1`, has now been fixed.
        However, the increased parallelism may result in increased memory use.
        Users who experience unwanted regressions should reset their
        `while_loop`'s `parallel_iterations` value to 1, which is consistent
        with prior behavior.