Why doesn't mplayer suggest a path with spaces in ubuntu 20?

Question

ubuntu

After upgrading to Ubuntu 20.04 (from 19.10), mplayer stopped suggesting paths when pressing Tab if a space was specified in the path (mplayer /tmp/hello\ world/). At the same time, ls and so on work fine (ls /tmp/hello\ world/hello\ world\ 2/).
The bug is also reproduced with a clean install of Ubuntu 20.04.
Maybe someone came across and solved?
How is the path hint for mplayer fundamentally different from the same ls ?
PS I know that spaces in Linux paths are a bad idea, but directories are created by Windows users