Function keys get stuck (stay pressed) - ui-automation

Question

I made Ctrl + Shift + X start a function using AutoIt, but using this the Ctrl and Shift keys get stuck held down. Inserting {CTRL up} and {SHIFT up} has no effect. Why does this happen?
My AutoIt script :
$dll = DllOpen("C:\Windows\System32\user32.dll")
Global Const $keys[8] = [0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0x5b, 0x5c]
;0xa0 LSHIFT
;0xa1 RSHIFT
;0xa2 LCTRL
;0xa3 RCTRL
;0xa4 LALT
;0xa5 RALT
;0x5b LWIN
;0x5c RWIN
HotKeySet("{PAUSE}", "stop")
HotKeySet("^X", test)
Opt("SendKeyDelay", 0)
Opt("SendKeyDownDelay", 0)
While True
Sleep(500)
WEnd
Func test()
Send("The control and shift keys are going to be stuck down at the end of this.")
Send("{ENTER}")
Send("{ENTER}")
Send("PlaceHolder,")
Send("{ENTER}")
Send("PlaceHolder")
Send("{TAB}")
Send("{HOME}")
Send("{LCTRL up}")
Send("{RCTRL up}")
Send("{LSHIFT up}")
Send("{RSHIFT up}")
Call("UnstickKeys")
EndFunc
Func UnstickKeys()
For $vkvalue In $keys
DllCall($dll, "int", "keybd_event", "int", $vkvalue, "int", 0, "long", 2, "long", 0) ;Release each key
Next
EndFunc
Func stop()
Exit
EndFunc ;==>stop the script

Answer 1

I modified your test function below. This solution has a problem because to run the function again you will need to let go of shift and ctrl and repress them. You can remove the dll call from your code. I also disabled the ^X hotkey while the function is being called. It's just safer that way.
Func test()
Hotkeyset("^X")
Send("The control and shift keys are going to be stuck down at the end of this.")
Send("{ENTER}")
Send("{ENTER}")
Send("PlaceHolder,")
Send("{ENTER}")
Send("PlaceHolder")
Send("{TAB}")
Send("{HOME}")
send("{CTRLDOWN}")
send("{CTRLUP}")
send("{SHIFTDOWN}")
send("{SHIFTUP}")
Hotkeyset("^X", "test")
EndFunc