Thomas, what is going on is probably another glitch..
Unfortunatelly, IT sector (or whoever gets paid for all those brilliant "improvements") obviously never use this platform, at least not as hosts. It is very user-unfriendly and it constantly changes (usually to worse.) I feel like a blind chicken trying to find a grain 😛
For example, I use "rule sets" (on PC) for certain days before and after each reservation to avoid a 1-night gaps between them.
Since the last month I can't access "rule sets" from multi-calendar anymore, I have to go to each listing's calendar to set it ( btw, way too many clicks and way too much time is needed to set it)
Once set, I can see the "rule set" and edit it from the multi-calendar.