Comment # 31 on bug 1054448 from Dr. Werner Fink

Btw: does any other curses based application show problems?  The new feature
added in ncurses-6.0-20170729 is

       + add "rep" to xterm-new, available since 1997/01/26 -TD

maybe YaST2 ncurses GUI can not handle this ... from man 5 terminfo

        Variable          Cap-      TCap       Description
        Numeric           name      Code
        [...]
        repeat_char       rep       rp         repeat char #1 #2
                                               times (P*)

if so this is not a bug of ncurses ... and from the pictures it looks like
repeating of an ANSI line graphic characters are not repeated well or the
smacs/rmacs switch is missed for repeating line graphic characters.