I just sent three correction notices (on the same quiz!!), and for the first two, forgot to change the radio button to read 'Disputing answer' instead of 'Typo/spelling'. I saw the option and remembered for the third one. Is this a problem on the other end, for editors reading the corrections?

Should be fine. The errors should speak for themselves.

The more information we have, to help us pinpoint thee problem, the better. However, as Kyle says, we can usually figure it out.