xdotool produces additional Tab if emulating Right, Left, Up or Down arrow key.

[Daresch]

The command xdotool key Right produces an additional Tab before sending the Right arrow.

You can see if in xev. The first block shows keysym Tab and after that comes keysym Right.

KeyPress event, serial 38, synthetic NO, window 0x5600001,
    root 0x6aa, subw 0x5600002, time 4377053, (48,41), root:(80,105),
    state 0x2000, keycode 77 (keysym 0xff09, Tab), same_screen YES,
    XKeysymToKeycode returns keycode: 23
    XLookupString gives 1 bytes: (09) "	"
    XmbLookupString gives 1 bytes: (09) "	"
    XFilterEvent returns: False

KeyPress event, serial 39, synthetic NO, window 0x5600001,
    root 0x6aa, subw 0x5600002, time 4377058, (48,41), root:(80,105),
    state 0x2010, keycode 41 (keysym 0xff53, Right), same_screen YES,
    XKeysymToKeycode returns keycode: 114
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyRelease event, serial 39, synthetic NO, window 0x5600001,
    root 0x6aa, subw 0x5600002, time 4377065, (48,41), root:(80,105),
    state 0x2010, keycode 77 (keysym 0x8bd, notequal), same_screen YES,
    XLookupString gives 3 bytes: (e2 89 a0) "≠"
    XFilterEvent returns: False

KeyRelease event, serial 39, synthetic NO, window 0x5600001,
    root 0x6aa, subw 0x5600002, time 4377066, (48,41), root:(80,105),
    state 0x2000, keycode 41 (keysym 0x65, e), same_screen YES,
    XKeysymToKeycode returns keycode: 26
    XLookupString gives 1 bytes: (65) "e"
    XFilterEvent returns: False

I can observe the same behavior with Left, Up and Down arrow keys.

xdotool version: 3.20160805.1
System: Linux Mint 21.3 Cinnamon, Kernel 6.8.0-51-generic

[Daresch]

Can also confirm this in version 3.20211022.1