When running ArmA 3 with a Defender Cobra M5 joystick connected, the output of the mode selector switch (a three position selector) appears to be detected as a permanently pressed button by the game, when it is not supposed to be detected until or unless the mode position is changed between the three settings.

This was not the case in versions of ArmA 3 prior to mid 2017 at a guess. It has been a few months since I last changed my control configuration, so I am not sure exactly when the change happened to cause the current issue.

Other games such as Elite Dangerous correctly do not read the mode selector as a permanently pressed button.

When attempting to make control assignments, the mode selector switch output is added as an extra button press to every assignment. The game is incorrectly detecting the mode selector switch as a permanently pressed button when making control assignments.

This problem even interferes with selecting other joystick button selections for control assignments, making it impossible to configure the Defender Cobra M5 joystick in game.

Some change has been made in the way ArmA 3 interprets DirectInput, resulting in misinterpretation of the Cobra M5 mode selector switch.
It is an issue between ArmA 3 and DirectInput rather than DirectInput itself, as it does not affect the Cobra M5 in other games such as Elite Dangerous
The problem never used to be present in earlier versions of ArmA 3

Note:
I have set the severity to 'Major' because it is a major issue if you use a Defender Cobra M5 joystick
Severity is how bad a problem is, not how many people are affected