Macroblocking and Halos

Bridge CC 20188 previews have horrible JPEG artifacts - macroblocking and halos:

All the relevant settings (unless I miss something) are checked - Generate Monitor-Size Previews, Always High Quality, Generate 100% Previews. Tried setting Use Software Rendering on/off too.

It seems to be a rendering bug. The actual 100% preview JPEG file in "...Adobe\Bridge CC 2018\Cache\full\..." folder is quite large (13.5 MB, 7952 x 4473 px) and manifests no artifacts when rendered in other applications. Another variant of the preview file in "...Adobe\Bridge CC 2018\Cache\1024\..." folder is much smaller (889 KB, 1920 x 1080 px) and does have the artifacts.

Is there any way to make full size preview files used for Full Screen Preview and Slideshow?