It is allowed and legitimate to use Google Cloud Platform virtual machines for FlexiCapture 12 on premises installation to deploy FlexiCapture 12 complex components, as any other allowed virtual machines. Such kind of installation does not violate FlexiCapture 12 specifications and falls under technical support responsibility.
However, special features of Google Cloud Platform are not supported. Note that the same is true for special features of Microsoft Azure and Amazon Cloud, which are listed in FlexiCapture 12 specifications.
Google Cloud Platform virtual machines are yet not tested by FlexiCapture 12 product team, so they are not added to specification. However, there are some examples of using them by clients with no specific issues.
Also it is known to use Google Cloud Platform virtual machines with other ABBYY DataCapture products: Recognition Server 4, FineReader Server 14.