Censored? Who changed my default posts from public to friends?

Censored? Who changed my default posts from public to friends?All my Facebook posts from March 8th through today,

every single one for the past 21 days,

had been set to friends only
- public default was turned off and it was not by me.

All posts from March 7th and prior were still marked as public.

When I went into settings the default had been reset to friends only.

WTF?