SqlGeneratorFactory is not thread safe

On our project we are running liquibase in multi thread mode (each schema in database update in parallel) and as result I have got error:

I think, it happens, because in time of calling method getGenerators in SqlGeneratorFactory class, we are using not thread safe structures for fields like: 'genericInterfacesCache', 'genericSuperClassCache', 'generatorsByKey'.

Please, help to resolve this issue.
Thank you in advance!