Hey there! I've noticed a behavior with some questions where I use both summary columns and custom columns (which include those summary fields in its formula).
In summary, after working for some time, the question suddenly throws an error (source sum column does not exist - image 1) and, upon checking the 'notebook editor', the summary columns are actually missing (image 3 vs. image 2).
Any input on how to avoid this would be very helpful! thanks
Hi @ruy
Could it be that "leads_table_view_query" does not have the columns "call_booked" and "project_booked" anymore? That would drop them from the summarize section, but if there's references in the Custom Column, then those are not always correctly cleaned up:
Custom columns not removed when a join is removed · Issue #14775 · metabase/metabase · GitHub - upvote by clicking 
on the first post
Hi @flamber , thanks for the reply.
The leads_table_view_query remains unchanged and still includes those columns, but the summary columns sometimes go missing for an unknown reason -- and consequently leads the custom columns to not work and the whole question to break (with similar error messages to the screenshot).
@ruy So this only happens sometimes? That sounds very strange. There's no consistency in when the problem occurs?
Can you include "Diagnostic Info" from Admin > Troubleshooting.
