Ref T13513. If your 10 most recently authored inlines have all been deleted, these queries can fail by overheating. This is silly and probably rarely happens outside of development.
For now, just let them overheat. This may create a false negative (incorrect "no draft" signal when the real condition is "drafts, but 10 most recent comments were deleted"). This could be sorted out later with a query mode like "executeAny()", perhaps.