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

As one example, IIRC earlier this year they lost some freshly launched satellites in a batch because of a flare, which made the atmosphere expand in density by up to 50% at their altitudes and didn't allow those satellites to point their solar panels at the sun in time.

Starlink sats are launched into a very low orbit and use their ion thrusters to raise into an operational orbit so any which happen to be nonfunctional deorbit very quickly (in the 2 months between this happening and it being reported, many of the involved satellites had already deorbited) and because it maximizes how many they can put up per launch.

So the satellites were lost, as they needed the panel pointed at the sun to sufficiently power the thrusters to overcome drag, but if they moved out of the safe mode orientation of having the solar panel edge point in the direction of motion, the drag would be too high.

Solar radiation pressure is a non-negligible perturbation to an orbit, especially during solar weather events.

If shielding is insufficient the control systems fry, or at least get wonked.

Article says 'burned' but also 'burned up', which I infer to mean, burned up during reentry, though it is not precise with the langauge.