Lightroom :: Black And White JPEGs With Colour Thumbnails?

I shoot on a Canon 600D in colour JPG mode. The camera is tethered to a laptop that runs some photo booth software. The software takes the images and makes a black and white image from them. After I have finished, I copy the individual (black and white) photos from one computer to another to work on them
 
My question is this:
 
When I open up the folder of JPG images or load them into Lightroom (library multi view) on the second computer. The thumbnails appear in colour and then after about 1 second, flick to black and white. When I open up the file in full/single view/windows viewer, the large image is in black and white.
 
Now given that the colour information is clearly embedded in the file somewhere - is there any way to get the full version in colour?
 
It's similar to if I shot RAW and it was showing me the embedded JPG preview - but as I say, at no point are the photos shot in RAW.
 
The colour profile is sRGB.