OK, so I came across an issue with the sandbox. Not sure if it's been scripted like this on purpose or not, but there's a definite limit on the number of characters (including spaces) that can be parsed. From the looks of it, after that limit is hit, everything gets sandwiched within an extra <html><body> set of tags and every line of code gets parsed with a <br /> at the end, killing the description and rendering it all wonky.
For me, the ceiling that I hit was 64,181 characters including spaces. I found that for every extraneous carriage return I deleted I gained an extra two characters to include.
I probably never would have come across this except for the fact that I'm coding a description for a 56-album soundtrack collection and, well, all that album info really adds up.
Can this be fixed or is it just something I'm gonna have to work around?