Looks like I have a similar issue since last update. No sound at startup on my laptop with integrated speakers, but it’s okay using headphones. Even funnier: I just have to plug and unplug immediately headphones, and the integrated speakers now work normally.
(Furthermore, at startup, only “Intel Kabylake HDMI” audio output is detected, instead of my Realtek ALC3246 audio chip, which is kinda weird.)
Please post more information about system:
inxi -SMAa
and audio devices detected in PulseAudio/PipeWire:
pactl list cards; pactl list sinks