Set M-values as distance: Multipart M-values are set in descending order

Question

I have a multipart polyline in an ArcGIS Pro 2.9.2 FGDB feature class (NAD83 UTM):

I can set the M-values to the cumulative distance of the line by using the Set As Distance tool (setting "Starting M" to zero):

That works as expected. Part #2's M-values are in the correct order (ascending).

However, if I do a different test, the results are unexpected:

• Drop the measures.

• Try a slightly different feature:

  Change the X-coordinate of part #1, vertex 2...from 130 meters to 135 meters.

• Re-do the test:

  Set the M-values to the cumulative distance of the line by using the Set As Distance tool (setting "Starting M" to zero).

Now, part #2's M-values are in the incorrect order (descending):

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Why are the M-values in the incorrect order? (descending)

I would expect the M-value order to be the same as the vertex index's order (ascending).

Answer 1

Esri says a defect: BUG-000148390.