Seems that the problem with % in directory names has come back.
I have a folder on sft called "100% Children". That directory hasn't changed for years and now with the 4.2.1 beta, the "Synchronisation Checklist" shows me that the whole directory first will be deleted locally, And the next line that the same directory will copied locally again.
With the former version (tested afterwards), there are no differences on this directory!
So it doesn't say that any file existing in the directory is changed!