grub-customizer wont start on Fedora 28 Workstation

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Hi to All Yesterday I upgraded successful my workstation to Fedora 28 (GNOME). When I start grub-customizer, I'm getting the following error:

*** initializing (w/o specified bootloader type)…
* reading partition info… /usr/include/c++/8/bits/basic_string.h:1048: std::__cxx11::basic_string<_CharT,
_Traits, _Alloc>::reference std::__cxx11::basic_string<_CharT,
_Traits, _Alloc>::operator[](std::__cxx11::basic_string<_CharT,
_Traits, _Alloc>::size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT,
_Traits, _Alloc>::reference = char&; std::__cxx11::basic_string<_CharT,
_Traits, _Alloc>::size_type = long unsigned int]: Assertion '__pos <= size()' failed.

I did a reinstallation and an installation from source. All time the same error. Can anybody help me to solve this problem? Thank you.