autocomplete is fail when using clang code model plugin

Qt Creator Can't autoComplete new button name when I using clang code model plugin。

for example, I rename a button from "button_old" to “button_new”. then autoComplete

ui->button_old not button_new.

it's ok when disable "clang code model" plugin.

Qt Creator 4.6.1 is ok also.

use qmake

when I create a default project,  it's ok before I build it first.

 if i build it, there are two "ui_mainwindow.h" files.

1>file1 path "AppData\Local\Temp\QtCreator-JQAirz\clang-uiheader-zrVMvy"

2>file2 path 'build-untitled2-DesktopQt5_15X86S-Debug"

now QtCreator Load the file2 not file1.

but when i change ui file,file1 is update. not file2.

so QtCreator can't autocomplete .

if I build project,file2 will update. 

use windows7 x64 and (Qt5.12.8 and Qt 5.15.0)