Found an issue with how a $match stage works with a function as part of the query.  It occurs when performing a search within an array.  There is an attached sample data file and a sample JS file for execution. The first and third aggregations work as expected; however the second fails.

It is assumed that comparing elements in an array against a literal (ie 2) should return the same as comparing elements in an array against a MULTIPLE(2, 1) function.

This pattern has been reduced down to the simplest form versus how we discovered this.  Our use case was matching into an array of objects post a $lookup stage to find root records that match a condition of documents in the $lookup array.

This was also proven to work against an array when $group was used.

It seems to not be tied to integers, numerics, dates, either.  Simple the use of a function in the match seems to be the issue.

The JS file is commented with notes and assumptions about expected behavior.

Thank you