Could you please provide the output of xev when you press that key?

For ':
KeyPress event, serial 26, synthetic NO, window 0x2800001,
    root 0x135, subw 0x0, time 2147049157, (166,74), root:(244,170),
    state 0x10, keycode 48 (keysym 0x27, apostrophe), same_screen YES,
    XLookupString gives 1 bytes: (27) "'"
    XmbLookupString gives 1 bytes: (27) "'"
    XFilterEvent returns: False

KeyRelease event, serial 29, synthetic NO, window 0x2800001,
    root 0x135, subw 0x0, time 2147049249, (166,74), root:(244,170),
    state 0x10, keycode 48 (keysym 0x27, apostrophe), same_screen YES,
    XLookupString gives 1 bytes: (27) "'"

For `:
KeyPress event, serial 29, synthetic NO, window 0x2800001,
    root 0x135, subw 0x0, time 2147123567, (954,404), root:(959,477),
    state 0x11, keycode 48 (keysym 0x60, grave), same_screen YES,
    XLookupString gives 1 bytes: (60) "`"
    XmbLookupString gives 1 bytes: (60) "`"
    XFilterEvent returns: False

KeyRelease event, serial 29, synthetic NO, window 0x2800001,
    root 0x135, subw 0x0, time 2147123632, (954,404), root:(959,477),
    state 0x11, keycode 48 (keysym 0x60, grave), same_screen YES,
    XLookupString gives 1 bytes: (60) "`"

The following key apostroph should NOT be dead!
KeyPress event, serial 29, synthetic NO, window 0x2800001,
    root 0x135, subw 0x0, time 2147210736, (867,406), root:(872,479),
    state 0x11, keycode 19 (keysym 0x27, apostrophe), same_screen YES,
    XKeysymToKeycode returns keycode: 48
    XLookupString gives 1 bytes: (27) "'"
    XmbLookupString gives 1 bytes: (27) "'"
    XFilterEvent returns: False

KeyRelease event, serial 29, synthetic NO, window 0x2800001,
    root 0x135, subw 0x0, time 2147210805, (867,406), root:(872,479),
    state 0x11, keycode 19 (keysym 0x27, apostrophe), same_screen YES,
    XKeysymToKeycode returns keycode: 48
    XLookupString gives 1 bytes: (27) "'"

The line you're interested in is in symbols/nl:
key <AC11>  { [dead_acute, dead_grave,   apostrophe,        grave ] };

Could you please try changing last two keysyms to whatever you think would be more appropriate?

This is a duplicate of 9603, symbols/nl has already been fixed in CVS.


*** This bug has been marked as a duplicate of bug 9603 ***