queue in Bookbinder calculated wrong when buffed

If having Bookbinder buffed the effect is calculated for entire production time, not taking into account if buff expires before production has been completed - how it works for Barracks and Provision Houses...

My Bookbinder is level 6 so normal production time for a Tome is 12 hours, with 'Hide Glue' added time is stated as 6 hours even though buff will end in 3 hours; correct production time should be 12h-3h = 9h.

https://image.prntscr.com/image/qXlW...tKVKuGP6cw.png