Have I found a bug? Alignment problemswith wide-char string

So I was trying to add some Unicode text to my app but it wasn't working, I tried to find out what the issue was and I got this:

Code:

format PE GUI 4.0
entry start
include "win32a.inc"
include "encoding/utf8.inc"

section '.bss' data readable writeable
msg MSG
hwnd dd 0

ASCIIText db 0
UnicodeText du "It worked!",0
section '.rsrc' resource data readable writeable

directory RT_DIALOG, dialogs
resource dialogs,\
1,LANG_NEUTRAL, main
dialog main, 'Unicode Test', 100, 100, 150, 20, WS_VISIBLE+WS_CAPTION+WS_SYSMENU+DS_FIXEDSYS+WS_MINIMIZEBOX
dialogitem 'STATIC',"It didn't work...",2,3,7,50,8,WS_VISIBLE
enddialog

section '.idata' import data readable writeable
library kernel, 'KERNEL32.DLL',\
        user, 'USER32.DLL'

import kernel,\
GetModuleHandle, 'GetModuleHandleA',\
ExitProcess, 'ExitProcess'

import user,\
CreateDialogParam, 'CreateDialogParamA',\
DestroyWindow, 'DestroyWindow',\
GetMessage, 'GetMessageA',\
SetDlgItemTextW, 'SetDlgItemTextW',\
IsDialogMessage, 'IsDialogMessageA'


section '.code' readable writeable executable

start:
invoke GetModuleHandle, 0
invoke CreateDialogParam,eax,1,0,DProc,0
cmp eax, 0
je DestroyDialog
mov [hwnd], eax
invoke SetDlgItemTextW,[hwnd],2, UnicodeText

StartLoop:
invoke GetMessage, msg, NULL, 0, 0
cmp eax, 1
jb DestroyDialog

invoke IsDialogMessage, [hwnd], msg
jmp StartLoop

proc DProc hwnddlg, msg, wparam, lparam
xor eax, eax
cmp [msg], WM_CLOSE
je DestroyDialog
ret

DestroyDialog:
invoke DestroyWindow, [hwnd]
invoke ExitProcess, 0
endp

For some reason, when 'ASCIIText db 0' is present before 'UnicodeText du "It worked!",0', the app wouldn't change the static element's text, but when I remove it, it works. If I put 'ASCIIText db 0' after 'UnicodeText du "It worked!",0', it works also. When ASCIIText looks something like 'ASCIIText db "a",0' it works as well. Am I not understanding something or is this a bug?