I am using pre-official beta 2903, but do not think the release caused the issue as I know I had my robust Outliner View with my Custom Metadata and a few other columns at such as for Total Word Count. When I went to look in Outline Mode to update a number of statuses at once, I noticed that all Culmuns I had previously tagged hag been untagged (in the menu drop-down for View\Outliner Coulmns.
I am not certain what may have caused this, but will rest them and keep an eye out for them again. I just earlier changed a few of my Status definitions, but doubt that would have had any impact… However, a few days ago, I was testing out many things and while I knew to stay away from Scrivenings Mode, I was checking out some Preferences and did check the box for Centering Titles and also Underlining Titles in Scrivenings, not realizing that it would actually change the content of Scrivenings (stupid on my part, now that I think about it). I have not use the Outliner Mode since then, so that may have been what caused the issues. Anyway, I will keep an eye on it to see if it happens again and if so, hopefully find out for sure what caused it.
I know this is not the forum for requesting new features, but it would be nice to be able to save report / tagged column formats and reload them as needed, as I can see value in having several customized views to choose from.
And just to be clear, I did not lose my Custom Metadata or the way I defined them (free-form, List, Check Box, Date,etc.) nor did I lose the contents of the MEtadata, I only lost the tags saying they were part of the Outliner Mode column listing.