FreeFileSync 7.1:when mirror, the empty folders on the right side remain

[yellowmisting]

Dear, I'm using the FreeFileSync ver.7.1, the mode "mirror from left to right" (for me this means mirror of the network to local disk).
My problem is that if any folder with files on the left side (on network) is deleted, and I launch the FFS, it correctly deletes all files on the right side, but (this is the issue) leaves the empty folder itself on my local disk.
The impact for me is that with the time I have many empty folders on my local disk.
What is wrong? Thanks.