How to workaround Query with a mixed-data column? (google sheets)

Question

I have a simple Query that groups my data by months that was working fine before, but now that I've introduced a formula into my date column, it's not working anymore. (I'm guessing it's because the majority data in the column is now formulas instead of actual dates).

=Query(C5:L,"SELECT SUM(I) pivot MONTH(C)+1",1)

Is there a way for me to still get my intended Query data without removing my formulas in the date column? (Query formula is in M2)

Thank you in advance!

Link to sheet: https://docs.google.com/spreadsheets/d/1EpvLMboKJ0KeR7tTqBarF1AnAg3jelhKTkyBhwKNlK4/edit#gid=1335125620

Answer 1

Your formulas in Col C seem to be causing the issue since they're adding a blank space when there is no corresponding value in Col D:

=IF(D45=""," ",TIMESTAMP())

Instead, try:

=IF(D45="",,TIMESTAMP())