is this a keyboard hardware limitation?

I have remapped Caps_Lock to Ctrl_L on an ancient mechanical keyboard.

It is still impossible to use the caps lock key to produce key combinations like C-e.

xev shows the following sequences are received when holding caps lock and pressing the e key:

KeyRelease event, serial 34, synthetic NO, window 0x2800001,
    root 0x250, subw 0x0, time 125662314, (4,-16), root:(5,382),
    state 0x4, keycode 66 (keysym 0xffe3, Control_L), same_screen YES,
    XKeysymToKeycode returns keycode: 37
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyPress event, serial 34, synthetic NO, window 0x2800001,
   root 0x250, subw 0x0, time 125663274, (4,-16), root:(5,382),
    state 0x0, keycode 26 (keysym 0x65, e), same_screen YES,
    XLookupString gives 1 bytes: (65) "e"
    XmbLookupString gives 1 bytes: (65) "e"
    XFilterEvent returns: False

Only when holding the actual left Ctrl key and pressing e is it producing the expected ^E control sequence:

KeyPress event, serial 34, synthetic NO, window 0x2800001,
    root 0x250, subw 0x0, time 125666946, (4,-16), root:(5,382),
    state 0x0, keycode 37 (keysym 0xffe3, Control_L), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyPress event, serial 34, synthetic NO, window 0x2800001,
    root 0x250, subw 0x0, time 125669530, (4,-16), root:(5,382),
    state 0x4, keycode 26 (keysym 0x65, e), same_screen YES,
    XLookupString gives 1 bytes: (05) "^E"
    XmbLookupString gives 1 bytes: (05) "^E"
    XFilterEvent returns: False

As it's shown that Caps_Lock's XKeysymToKeycode returns keycode: 37 I would like to know if it is possible to handle this in the event that it is a hardware limitation.

The keyboard is from an Apple IIcI, a computer was released in 1989.

What do you think could be causing this?