Let's use some logic. If the investigation was specifically triggered by SN8, then it's likely related to altitude/trajectory or landing. It's probably not altitude/trajectory since that seems like such a brain-dead thing to clear before hand. So it's probably the explosion-landing.

Btw: this is SpaceX's current license for operations at Boca Chica: https://www.faa.gov/about/office_org/headquarters_offices/as...

Obvious areas of conflict would be if SpaceX did not amend their license or notify the FAA to indicate that they believed they would likely not be able to safely land, or if SpaceX had stated that they they expected to be able to safely land. These would be areas that the FAA have a legitimate interest in.

Regulatory officials aren't idiots, especially with respect to high publicity subjects like SpaceX. If they KNOW that they are changing their own processes this year, they're not going to go trigger stupid shit over stuff that probably won't stick later, especially chasing against Elon. If they're bothering to do this, there's probably something worth looking into. Note that that's not the same thing as "SpaceX did something wrong".