Piefed scheduled posts disappearing

Hi all - as always, love Piefed, hate to complain - but I noticed this week that I used to have 3 Scheduled Posts, all going to the DailyGames community, and now I just have 1:

Do Scheduled posts have an expiration date or is there some other explanation for why they went away?

I am fine to go re-create them, that's not a problem, but I'd like to understand how this is expected to work. Thanks!