[Bug]: withOutputTags (aka side output) requires ParDo to run on each output separately

[shai-rubin]

What happened?

Apache Beam Java sdk version: 2.63.0 Spark version: 3.5.4

Running ParDo on a CoGrouped PCollection and expecting to retrieve multiple outputs using withOutputTags.

On Spark UI I see that the ParDo runs on each "output" separately instead of 1 time for all.

Issue Priority

Priority: 2 (default / most bugs should be filed as P2)

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