No, the corruptions are essentially the whole right 4 columns that look red and the column at about a third from the left. These look different than they should. Try for example to go to 58 or 59 chars for the image, you will notice the picture will not have these corruptions.
Maybe better to take a step back and investigate "normal"-bitmap modes (640x200 with 8 lines char-height) first and work your way up to the modes from VDC-Mania. I'd soggest to start with HFLI there (640x400 non-interlace), then go to the different interlace-modes. Or maybe even try the modes from VDC VGA Mania if your device can display these. I just connect my RGBI-DAC to the VGA-input of my LCD-TV for those.
The 8x1-FLI-mode is a hack in itself, since it resets the charheight to 8 in the VBLANK-area and back to 1 once the picture starts, so this may cause other effects.
On another note: We never managed to get modes with more than 80 chars working with attributes enabled. If I remember correctly, willmanilly thought these may be due to internal buffers that are "full". I seem to remember the corruptions looks similar if you try graphic-modes with >640 pixels and attributes enabled.