Unexpected @@rowcount behavior inside an UDF in MS SQL 2019

Scalar udf inlining yet again, rather buggy

SELECT dbo.rowcount_test()

OPTION (USE HINT('DISABLE_TSQL_SCALAR_UDF_INLINING'));

This should be fixed now.

https://support.microsoft.com/en-us/help/4538581/fix-scalar-udf-inlining-issues-in-sql-server-2019

This cumulative update also blocks Inlining in the following scenarios:

• If the UDF references certain intrinsic functions (e.g. @@ROWCOUNT) that may alter the results when Inlined