In a nutshell, the ‘insider’ gives instructions to a broker such as ‘on the 2nd Wednesday of every 3rd month, sell X number of shares if the market price is no

In a nutshell, the ‘insider’ gives instructions to a broker such as ‘on the 2nd Wednesday of every 3rd month, sell X number of shares if the market price is no less than Y’ and the broker executes on those instructions without any further contact with the insider. The instructions are typically given well in advance of the first sale (and there is typically a schedule of sales rather than one-off sales). So as the GP said… nothing to see here.