Unable to Group by Month on Pivot Tables.

I have a weird situation that I can't find a solution to online. If I export my Power Query* query into a table then make a pivot table out of that, the option to group by months automatically comes out. But if I export my query directly into pivot table, Excel won't let me group my dates into months - group field, group selection, all those don't work. Any idea why this is happening? It can't be the format cause query>table>pivot table works. The second pivot table is loaded into the data model.* Could this be the reason why?

*edited

Edit2: using DATEVALUE() on a Pivot Table date gives a #VALUE error. Is there any info how Pivot Table formats dates? Wrapping the date in a TEXT(,"m-dd-yyyy") fixes it.

The left indent on the right PT could be a clue but I don't know how to interpret that.