Premiere Pro CC takes hours to finish proxie creation

I've been taking R3D files (31 in this batch) and ingesting them as Proxies only unto my MacPro2017. I elected Metal, as it seems to be quicker than OpenGL. I selected the files from PPCC Media Browser, right clicked and selected Import. The Ingest is simply set to produce Proxies only on the local ssd drive in ProRes format. They appear to have imported properly, and I can see them in my destination folder using Finder, and Media Encoder shows it has finished its job. But when I return to the PPCC window the app is non-responsive. Last night I had the same issue, and basically let it run the the night, and it was fine by morning. So I repeated my import process again for other R3D files today, and it stalls at the same point. I see no indication from PPCC of what activity it is performing or any issues it is having. How do I see what the underlying issue is? Should I do smaller batches? What is PPCC doing that requires it to keep processing although the files appear in Finder and I can scrub through them from finder? I thought once Encoder was done, that all the processing was done, and PPCC would be unencumbered by any additional processes. I also tried to eject the external hard drive from which holds the source media, but Finder does not allow me. It says PPCC is still using the files - but I can clearly see the external disk is asleep as there is no blinking light showing activity.