The Technology and Construction Court claim is thought to relate to a £3 million art and technology building completed in 1999.
The project, which replaced a redundant boarding house, comprises five floors of art studios, workshops and food technology laboratories.
The building won a Cheltenham Civic Trust Award in March 2000.
Oxford Architects' brief also included a full accommodation and curriculum audit carried out in 1994.
The practice hit the headlines at the beginning of the year when its £18 million animal-research facility at Oxford University was dogged by threats from animal rights extremists.
Property belonging to Oxford Architects was reportedly vandalised, and construction was halted after activists targeted contractor Montpellier.