This is likely a Stack Exchange wide problem, but I've only so far noticed it in our Space Exploration's Community Bulletin box. Probably because we must be the Stack Exchange leaders in how many community events we schedule, so it's frequent that our Yellow Box™ displays maximum number of items it was set up to display.
Each time the Community Bulletin displays a featured post from Meta Stack Exchange, the Yellow Box™ only displays three (3) items, instead of the usual five (5). This problem is manifesting itself since the Meta Stack Overflow to MSO and MSE split. Interestingly, this symptom does not manifest itself in our own Space Exploration Meta, but it doesn't display the featured MSE post at all:
Now, the problem for us is, that nearly all of our scheduled community events are broadcast live, frequently interactive and accepting questions from the audience, and of course they're publicly available and our members would chat about current events in our main chat room (The Pod Bay). Often, there's many of them in a single day, so we really need those few more slots in the Yellow Box™ to give our members ample warning they really ought to make room in their schedule for events they're most interested in.
TL;DR - Displaying a single community event in the Community Bulletin, when a MSE post features in it, is not enough. At least four items relevant to a specific community (a mix of community events and featured community meta posts) should display in the Community Bulletin, with one slot reserved for network-wide announcements. When there's no network-wide announcements, all five slots should be available for promotion of activities specific to that particular community. For some reason, post MSE and MSO split, whenever there's a MSE post featured in our Yellow Box™, the list of items shrinks to three (3), instead of five (5). Not cool!