When the user has multiple layouts installed the Robot can target the wrong keys when generating press and release events. This can also happen if the user has only one layout installed if it's not a U.S. layout; under the hood there is often a second U.S. layout that's not visible to the user. This can cause failures in the manual KeyboardTest application in tests/manual/events.

Alternatively you can run the attached manual test. Install French and English layouts in whatever order and make the second one active. Run the RobotKeySanityTest and press the alphabet keys. Wherever the layouts don't match the test will fail.

Under the hood the Robot code is asking for a list of all hardware keycodes that can generate the given keyval. It then just picks the first on the list without checking the group or shift level.