I've not situated these occasional events yet, but
When I Ctrl-’ into a single-editor view, the editor might have no header bar. When this happens, shifting back to my usual two-editor view does not restore the header to the particular editor: That is, shifting back yields one editor without the header, the other with the header.(Perhaps a memory thing? A late-in-the-day or video event? As I recall the latest was later in the day's session ... I'll attend more next time.)
Among the Project Search options, the ‘exclude Trash …’ gets unchecked, so far unpredictably, more during/after a restart of Scrivener, rarely during a session. (I don't often tweak the settings nearby.)Of the two, the former is less likely -- rare. (Twice?)
The latter, occasional: For example, not during the past week.