Running the Pinecil off a Riden bench PSU with a simple DC power plug is rock solid, for comparison.
Here's a similar report by someone else: https://www.reddit.com/r/PINE64official/comments/qq7wv8/pine...
I've seen a few others.
Given the complexities of USB PD, it could also be on the side of the iron and then down to the version of IronOS. The other reporter mentions it works fine with other chargers, but that doesn't speak to correctness/compliance. I did not investigate much since my bench PSU is right below the PinePower on my workbench :)
I will say it generally works nicely with the little USB-C-equipped power delivery breakout boards I use in projects, or MCU boards I've tried. I also park my phone on it a lot. So I am getting use out of it.