How to recalc a virtual_libraries() column?

I run into an rare glitch where my virtual_libraries() template starts reporting 'recursion detected' when there actually isn't any -- I can't reliably replicate it yet, but I noticed it sometimes happens after I run an action chain that modifies several columns in sequence (maybe the template processor is confused by the values rapidly changing?)

Restarting Calibre fixes the issue, but is there another way to re-calculate the column?