It's a fact all missing Saturday cards were always already loaded on iS servers (since all Calendar users had even been able to download them on Friday); so, I might be wrong but I would think that - if an automatic release fails - it might also be easy and fast for a Team member whatsoever doing a manual general release even from remote; therefore, I was sort of surprised people which are not suscribed to Calendar promo had to wait the following Monday on all weekends of december.
Indeed, since this issue is, by now, known to happen on every saturday of the promo, it looks almost strange no one did plan in advance to get it fixed manually on each Saturday morning - neither prior neither after users did report it.
Lets go back to 7 releases during the work week, and do the same during calendars. A person can simply choose not to open their advent release until Saturday or Sunday.
If anyway if would be not possible to get a fix about releases during weekends (as it looked not to be), this one could be a solution, yes.