Emulator

Game Name?

Tested with Mario Kart Double Dash, Mario Kart Wii and Mario Party 4

Game ID? (right click the game in the game list, properties, info tab)

GM4E01, RMCE01 and GMPE01

What's the problem? Describe what went wrong.

When playing back a .dtm replay file, some buttons pressed on the controller are accepted by the emulator.

What steps will reproduce the problem?

Example here is Double Dash. Start recording input and go into a race. Leave the race running for a few seconds without pressing anything and then close the emulator and save a replay file.
Then, play back the replay and press the start button at the start of the race while it's still playing back input. The pause screen should come up. A faster easier way to test this is simply to not pressing anything during the intro movie during recording and then press start during the replay.

Is the issue present in the latest development version? For future reference, please also write down the version number of the latest development version.

Yes, present on 5.0-9751.

Is the issue present in the latest stable version?

No, it's not in 5.0.

If the issue isn't present in the latest stable version, which is the first broken version? (You can find the first broken version by bisecting. Windows users can use the tool https://forums.dolphin-emu.org/Thread-green-notice-development-thread-unofficial-dolphin-bisection-tool-for-finding-broken-builds and anyone who is building Dolphin on their own can use git bisect.)

5.0-5911 is the first broken version while there is no problem with 5.0-5907. Note that the replay has to be made on 5.0-5911 to see this problem normally. If the replay is made on 5.0-5907 but played on 5.0-5911, the replay plays with nothing happening, but the button inputs aren't accepted like they are when the replay is made with 5.0-5911.
This issue only seems to affect Gamecube controllers (both as a standard controller and the adapter for Wii U). I haven't noticed this problem with emulated Wii remotes.