Does SQL Server CASE statement evaluate all conditions or exit on first TRUE condition?
•Returns the result_expression of the first input_expression = when_expression that evaluates to TRUE.
Reference
https://docs.microsoft.com/sql/t-sql/language-elements/case-transact-sql

This is standard SQL behaviour:

A CASE expression evaluates to the first true condition.

If there is no true condition, it evaluates to the ELSE part.

If there is no true condition and no ELSE part, it evaluates to NULL.