I forgot to mention (sorry) the time data is coming from a lookup. ARRAYUNIQUE and ARRAYFLATTEN don’t seem to be doing the trick, so it’s returning an #ERROR. The lookup is already formatted as an Integer and it works for doing basic math, so super odd.
@ucmavnerd Not a bug. That’s just how lookup fields behave. More often than not, they return arrays of values, even when there’s only a single value being looked up. I broke down all field types in this base, which shows how they’re treated on their own in formulas, as well as how they’re treated when fed through a lookup field.