VIAVI TestCenter: B2 Appliance - Ports do not come up after DUT changes speed from 400G to 800G and back to 400G.

Having the following connectivity STC port 1/10 DUT port 1/9(400G). Initially, STC ports come up when the speed is set to 400G and: AN=OFF | FEC = ON on both sides (DUT and STC)Tx and Rx precoding are enabled under L1ConfigGroup - AN/LT transceiver. Then, when changing the speed to 800G on the DUT the ports on STC go to red as they should (Expected) But, when changing the speed back to 400G on the DUT port, the STC ports do not become green, instead to bring them up the customer has to release the STC ports, reserve the STC ports again, and hence enable the TX, RX precoder on STC and then STC ports come up as green. - Sometimes the customer needs to reboot the DUT and wait for a few minutes to be able and bring the STC ports up again.  

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