Button widget not correctly aligning in grid with sticky = 'nsew' when the button does not have text

The button widget seems to not properly apply the sticky attribute when using the grid manager if the text of the button is empty, i.e. text = ''.

    app = ctk.CTk()
    app.geometry(str(1280) + 'x' + str(720) + '+0+0')
    app.rowconfigure(0, weight=1, uniform='u')
    app.columnconfigure(0, weight=1, uniform='u')
    frame = ctk.CTkFrame(master=app, corner_radius=0, fg_color='gray')
    frame.grid(row=0, column=0, sticky='nsew')
    frame.grid_rowconfigure((0, 1, 2, 3, 4), weight = 1, uniform='u')
    frame.columnconfigure((0, 1), weight = 1, uniform='u')
    buttons = []
    for r in range(5):
        btn_array = []
        for c in range(2):
            btn_array.append(ctk.CTkButton(master=frame, text = '', corner_radius=0))
            btn_array[-1].configure(fg_color='white', text_color='black', state='enabled')
            btn_array[-1].grid(row=r, column=c, sticky="nsew", pady=2, padx=4)
        buttons.append(btn_array)
    app.mainloop()

If the button is initialized with text and then the text is set to '' using configure, the sticky property seems to work correctly.

Start by running the provided CTkButton grid example with text='' and compare it with a button initialized with text before configure sets it to empty. Trace the CTkButton initialization and grid behavior to identify why sticky='nsew' differs, then verify the same layout works for empty-text buttons without the workaround.