Invoice Report doesn't calculate sum of Balance

vtiger 7.4.0

Create a few invoices and add some received money so you get a balance value.

Create a normal report and select the Invoice-Balance field for SUM.

Run the report.

The result is empty even though there are values in the Balance field.

We've just encountered the same issue with a couple of fields that weren't being calculated even though they had values, and traced it back to the field label. Our field labels contained £ symbols, which at some point appear to be url_encoded and then aren't being decoded later.

We're looking into a fix for this currently - maybe this is caused by a similar problem?