Example shown in the referenced project are the two resistors on pins CC1 and CC2 for the USB-C port. Both resistors should go to ground, but the ground pour doesn't flow in to connect to them.

Unfortunately I've since fixed the problem in the sub-Component/Module/Assembly/Layout and didn't clone it when I did, so I can't reference to the sub-Component/Module/Assembly/Layout highlighting the problem. The remedy seems to be to "kick" Flux a bit by moving a part around to trigger it to reflow the ground pour. In some circumstances, like shown in this project, it's a persistent issue, but other times I've witnessed this happen, a simple refresh of the browser will then show the ground pour properly flowed where it should be. Problem is, if you export your Gerbers while it's "temporarily" not flowing correctly, you're hosed.

When this occurred originally, and as you can see in this project, there's no missing airwire for those resistors. Recently though when I saw this happen similarly, it did complain about the missing ground connection with an airwire. That said, there was no reason it couldn't flow the ground pour in to fix it. Refreshed the browser, and that fixed the ground pour and the airwire vanished. For reference, this most recent incarnation of the issue I saw using Safari Version 18.0 (20619.1.26.31.6) (yesterday).

Either way, terrifying issue. It's lead to at least one botched board run and the purest form of anxiety looking over my Gerbers post export to ensure none of the grounds necessary got missed.