Thank you for your reply. I transferred the Rosetta at home work onto a system image using the same computer but running Windows 10 build 19042.867 instead of Linux Deepin 15.11. I found that it runs all the original tasks without computation errors on that Windows 10 Pro image.
It looks like Rah is either fundamentally fighting Linux Deepin 15.11 or it just doesn't like the tasks which maybe are not configured for running on Linux. No way of knowing I guess!
No problems switching system images using Macrium Reflect other than the Linux Backups and Restores take 2 hours to complete, rather than 10 minutes with Windows. Also Linux doesn't file-share on a mixed Linux/Windows 10 network. So - on balance, I will probably run a few swap-overs to see how things shape-up but stick with Windows 10 until these major problems are corrected.
Thank you PineyCreek, you were very helpful. I am grateful.