Or just stochastic impacts with debris too small to track. Objects >1 cm are fatal to satellites, but ground radar can only track objects 10 cm or larger.

The two scenarios are pretty easy to distinguish. If the explosion occurred near the poles (above 75° latitude), it's most likely a random debris strike.

Sure enough, despite the fact that only 2.1% of Starlink satellites[0] are in orbits that go above 75° N/S, Starlink-34343 was one of those satellites.[1]

[0] https://planet4589.org/space/con/star/stats.html

[1] https://www.amsat-uk.n2yo.net/satellite/?s=64157

Astronomers? I know they don't like starlink satellites. Might somebody have access to a powerful enough laser?

A rate of one collision per year per 10,000 satellites, in a low orbit where debris is quickly removed by drag, seems perfectly manageable.