Pcell will be expecting the HARQ feedback of Scell but UE failed to decode the Scell PDCCH . This case UE doesn't send the CA HARQ and uses different PUCCH format But PCELL will be expecting different format to receive the feedback. How to overcome this issue.
gNB can intiate RACH procedure for PDCCH order. But If UE is configured with NUL and SUL , then How UE comes to know for which UL carrier it has to initiate PDCCH order.