Simultaneous RRS=1 and FDF
According to ISO TC 7.1.4 IUT shall be able to receive CAN FD frame where RRS bit is high.
In current implementation RTR flag is sampled in position of RRS bit and this is used to decide that no data field will be contained in that frame (as if RTR frame). In case of CAN FD frame (FDF = 1), this information shall be ignored however.