Created attachment 113866 [details] Screen where doesn't save these 2 values The keyboard's values delay and speed aren't saved since System's Preferences > Keyboard Configuration. Yes are saved the values, only the values as it visually appear but they're not functional. Moreover, in Input Devices > Keyboard , appear the old values put in previous screen (but not functionals). My model keyboard is Generic using spanish language.
Could you check how the application/process name is called when you invoke that dialog? Simplest is to use Ctrl+Esc to monitor. I get a different looking dialog in systemsettings. Please compare to the dialog when you run "kcmshell5 kcm_keyboard" in Konsole.
The name is "systemsettings5" when I access keyboard dialog through System Settings menu. It's a little weird when I run "kcmshell5 kcm_keyboard" as it the process name "systemsettings5" no longer appears. Instead of the process is "kcmshell5" though must be the regular. In the keyboard dialog loaded through "kcmshell5 kcm_keyboard", the test field where you can try out the config, turn out doesn't detect the values of keyboard repeat. If I change the lag value to 275 (current mine) to another and after I write in test field, isn't affected in the keyboard config. This happen in this dialog by the previous command like in Input Devices menu of System Settings.
Hello! Sorry to be the bearer of bad news, but this project has been unmaintained for many years so I will be closing this bug.