Cotswolds Railcard - Is it still valid for off-peak period returns?

[Gagravarr]

It's been a while since I had a Cotswolds railcard, as my Network Goldcard works for the same route, but the other half has hit a problem today with hers...

Based on past use, the the National Rail enquiries website description, it's valid for
The Cotswold Line Railcard gives the holder a 34% discount from Off Peak Single and Return tickets, and Anytime Day tickets on the route between Worcester Foregate Street & Oxford inclusive.

However, the staff at Oxford today claimed it's only valid on day returns whether Anytime or Off-Peak. Looking at brfares that seems to match, but that's not what I'd expect...

Have GWR recently tightened up the rules for the Cotswolds Line Railcard and off-peak (period) returns? And/or did they do it knowingly, or is this a mistake?

 

[Romilly]

GWR's April 2018 leaflet for this railcard says:

Who is it for?
Anyone aged 16 years or over can apply for a Cotswold Line Railcard

Which tickets do I receive discounts on?
Cotswold Line railcard holders receive 1/3 off the price of Standard Class Single and Day Return tickets for travel wholly with the Cotswold Line Railcard area.

Discounts are applied on all Off-Peak services on Mondays to Fridays and all day on Saturdays, Sundays and Bank Holidays.

On Mondays to Fridays the first services on which the railcard discount is available are:
Towards Oxford: 0825 from Worcester Foregate Street to Oxford
Towards Worcester: 0851 from Oxford to Great Malvern.

* The Cotswold Railcard is NOT valid on the morning service from Ascott-under-Wychwood, Finstock or Combe.

And the GWR website currently says:

Cotswolds Line Railcard
The benefits
Save a 1/3 on Standard Class train tickets if you’re travelling between Worcester Foregate Street and Oxford.

If you’re travelling Monday to Friday, discounts apply on Off-Peak Single and Return train tickets from 08:25 towards Oxford and from 08:51 towards Worcester Foregate Street. Railcard discount applies all-day on weekends and public holidays.