Chord Symbols - spaces instead of typed keys

When entering a sequence of chord symbols, intermittently the symbol text simply fills with spaces instead of the keys typed - one space per key. I have not been able to find any trigger for this behaviour. Having filled with spaces, moving to the next symbol (with TAB or SPACE) means the space-filled symbol doesn't exist (which would be expected). Running 2.0.2, revision f51dc11, on Windows XP.