Cassidy was seeking to follow up his third place from the opening London race, in which he was promoted from fourth after Nyck de Vries was handed a penalty for weaving in front of him in defence.
Instead, the New Zealander was dealt damage to his suspension and his rear-left tyre in an early tangle with Gunther - and under the safety car was seen driving close to the pitwall for his team to assess the damage.
