[Regression] Artefacts after 9.1.2125 with DirectX

[Axel Bender]

OS: Windows 10 (MingW64)
Gvim: 9.1.2127

Preceeding as described in the below file, removing characters leaves artefacts.

File
-------------------------------------------------------
     a["xxx"] = yyy;
     a["xxx"] = yyy;

" I did the following:
" 1) gvim.exe -i NONE -N -u NONE --noplugin -U NONE <this_file>
" 2) gg
" 3) xxxxxxxx

" vi: renderoptions=type\:directx,renmode\:6 linespace=0
-------------------------------------------------------
Result (on my machine):

[Maxim Kim]

Additionally 

set fillchars=vert:│

now doesn't look contiguous