[Rebelgecko]

Dunno if it's what happened in this case, but solar flares make the atmosphere bigger* which increases drag on satellites in low Earth orbit.

That said, the satellites have an expected life of 5 years so it's not necessarily a big deal. Their planned constellation is so large that it's dependent on having a nearly continuous churn of replacement satellites.

* This is a bit of an oversimplification

[yread]

The atmosphere becomes less geoid-shaped during flares, right?

[bagels]

Day night cycles already do that. The atmosphere expands during solar storms, increasing drag.