Annoying issue -

I have an annoying issue. I have a lenovo thinkpad S145-15IIL, running big sur. Everything works fine. Audio, bluetooth, wlan, graphics acceleration, etc. However. About halfway through the boot sequence, the screen dims to about 80%. (What I mean here is maximum brightness is only about 80% of what it should be, after logging in I see the slider at max, hot keys show max) If I put the machine to sleep, the screen is back to full brightness when it wakes up. Annoying.... any ideas?