Something you've done or some upgrade is triggering or auto-starting kglobalaccel5.
It somehow takes precedence over Openbox' own keybindings, and will bring up random/sometimes coincidentally related KDE/Plasma program, set by default (or not) to the same keybindings.
It can perhaps be triggered by some "random" KDE programs you start, I guess depending on environment variables and whatnot. Besides eventually being set up in some kind of xdg-autostart thing...