The DML flow consists of simple INSERT / UPDATE / DELETE and also BEGIN/COMMIT which are executed in several threads each of which has set a session value of gtid_domain_id equal to CONNECTION_ID (hence it's unique for every thread). Replication (row-based) promptly fails, and after that an assertion failure happens. I assume that the assertion failure is one of those known issues with error handling, but the replication failure itself shouldn't be happening at the first place.
The result is the same whether the slave uses GTID or not. In the standard RQG it does not, but if you want to try with GTID, you can either start the servers separately, or apply the patch for RQG provided below.
RQG grammar (parallel-replication-2.yy):
RQG command line:
RQG patch to use GTID: