Question marks in front of amount in transaction report

[Sanjay Chakravarty]

Dear users

I have Gnucash 2.6.18 running on Arch Linux. When I create a report, I 
get 3 question marks in front of my "Amount" like ???50.0. This is 
happening in report only, and the accounting tables are fine.

Currency is set to INR. Font is Roboto in the HTML Stylesheet.

How can I get rid of the question mark characters in the report?

Warm regards
Sanjay