Please note that reflector-simple and reflector are separate apps.
reflector-simple is essentially a GUI wrapper around reflector.
reflector-simple is an EndeavourOS in-house app.
reflector is from Arch and made by Xyne.
If reflector has issues, see https://xyne.archlinux.ca/projects/reflector and https://www.archlinux.org/packages/community/any/reflector for more info.
reflector bug reports can be given at https://bugs.archlinux.org/?project=5&string=reflector.