PIO mode in Raspberry Pico

[carl336]

Hardware： Raspberry Pi Pico
Software Development Environment： Micropython
Purpose： Turn on a backlight（the backlight is producing at present, so now I only have LED driver specification：https://imgur.com/MfJhHsf
）
Hello, I am a beginner, learning Micropython with Raspberry Pico.
I am using PIO mode of Raspberry Pico.
First of all, here is the code that I wrote: (simulate SPI by using PIO)
https://paste.fastmirror.net/?b1f8b4a18cce1339#43mFFTQijtTs9ycsDgabJuzbAbPu6PGjHiysuiyAN138
I appended 0x4060,0x4F6F to 0x2040,0x2F4F, then the data did not detect 0x4060,0x4F6F in the timing diagram detected with the logic analyzer.
https://imgur.com/XvNSus1
So, when I modified 【autopush=True 】to 【autopush=False】, it detected 0x4060,0x4F6F.
https://imgur.com/qeU3Irc

Why is this happened? Can anyone explain this to me? Please!!!