As discussed in this lj_dev post, the music field can get terminated. This leads to situations like this talkread page where the music field actually has a link in it (which might not be a good idea to allow anyway) but it gets snipped in the middle of the href URL, leading to gross ugliness. Something in the code (htmlclean?) goes crazy and starts URL-escaping a massive amount of text. Unfortunately, I'm not quite sure how to fix it right now. This isn't just a problem for talkread; it can mess up lastn and friends pages too.
Note that merely fixing the truncation thing won't fix this; if you manually type in a music field that ends in the middle of a quoted thing in a tag attribute, the same bug will happen.
Perhaps logprop fields need to be somehow cleaned before being inserted into text?