Folds are open on editing a new .src file

[KnoP-01]

Even though g:krlFoldLevel is explicitly set folds are all open on opening a .src file.

Without using
call plug#begin('~/.vim/plugged')
all is fine...

[KnoP-01]

I can come around this bug with

call plug#end()
syntax off " undo what plug#begin() did to syntax
filetype plugin indent off " undo what plugin#begin() did to filetype
syntax on " before filetype plugin on
filetype plugin indent on " after syntax on

The main reason for this bug is that there are

syn region krlFold

commands not in the syntax file but in the ftplugin. That is probably bad practice. I have to move some functions (KrlIsVkrc() in particular) to autoload and move the syn commands to the syntax file.