Investigators largely suspect directed-energy attacks behind Havana Syndrome (politico.com)

Directed-energy attacks would be easily detected. They haven't been in any of the world-wide cases.

Washington DC is very likely crawling with detectors of all types. But there were 'attacks' in Washington DC, and nothing detected.

I venture say that we will find that these occurrences are not attacks, but something else and are unintended consequences of some other activity.