The issue is now identified. CloneBD has a tiny but effective bug when doing lossless partial Ultra HD copies. In that specific case, it uses the Bluray muxing rate instead of UHD. It does not affect MKVs. A fix will be available soon.
I installed the latest version of CloneBD. It rips the movie but will not create an ISO image. The 50 something GB disk produced a 104GB temporary directory. Log file attached. Thanks