Grand total rows summing percentages

I have an issue with ERPNext Reports for Purchase Orders. The total row incorrectly sums percentage columns.
Here’s an example from v12.22

PO1 is placed for 5 items, PO2 for 3 items (€1 per item).
On Day 1 they are both at 0% billed as I have not been billed for any goods. The total row in the report shows 0%.
On Day 2 I get billed for 5 items for PO1. PO1 is shown as 100% and PO2 as 0%. The total row in the report shows 100%.


The total row is wrong.

I cannot have been billed for 100% of the orders listed in the report (PO1 and PO2) because I have not been billed for PO2.

PO1 = 5/5 = 100%

PO2 = 0/3 = 0%

(items billed)/(items ordered) = %age billed

(5+0)/(3+5) = 62.5%

(The same applies for %received.)

Is anyone else seeing the same issue?