I don't recall seeing anything like that reported before. It's odd to see a recognizable but corrupt image, most of the corruption I've seen is totally incorrect data.
It would be interesting to know if shooting with an intervalometer script on the camera without remote shoot produced the same results or not. You could use my fixedint script to do this:
http://chdk.wikia.com/wiki/Lua/Scripts:_Fixed_Exposure_IntervalometerSettings I'd suggest
interval 50 for 5 second interval
Tv to something that gives you are recognizable image (Leave Tv=0 and use Tv + sec/10000 if you need shorter than 1/64)
Use raw off
Use cont mode unchecked
You should be able to leave the default values on the other
I also tried turning off the display using the following, but couldn't get that to work since the display switched on again as soon as the remote shooting started.
This might be caused by having review enabled in the canon firmware. If it is enabled, it might be worth trying with it off.
You could also try using continuous mode rather than "quick" (-cont=... instead of -quick). You'll need to ensure continuous mode is enabled in the canon firmware, which needs to be done after every boot on older cameras.