How can I include mirror cards when a filter a board by label(s)?

[Scott Stilson]

You folks do appear to have recently enabled viewing mirror cards when filtering by just about any other possible filter, such as card member. However, despite the presence of “Also unable to search mirror cards based on labels” in the User Problem section of that Jira issue’s Description and that issue having been marked Closed, it is still the case that none of the labels assigned to mirror cards appear among the Labels filters in the Filter cards menu:

[Scott Stilson]

Upon further troubleshooting, it appears that if I manually add the label by which I wish to filter natively to the board on which the pre-labeled mirror cards sit, then that label both appears among the Labels filters in the Filter cards menu and, when clicked in that menu, results in the mirror cards so labeled being in the filtered view. That, I suppose, is a temporarily acceptable workaround. 

However, since there is no way to add labels across a workspace, or even to copy sets of labels to other boards, then the absence of the automatic addition of labels to boards, as happens when you copy or move a regular card to a board, necessitates unnecessary admin overheard. How many times will I need to manually add the same set of labels to boards?