My 1.5.8 (1496) quits each time I try this:

Open a blank document.
Type opening brace i.e. {
TM inserts closing brace i.e. }
Press Ctrl+k to kill closing brace
Press backspace to get rid of opening brace
TM crashes.

This seems to happen only if I used Ctrl+k to delete the closing brace.
If I place the cursor to the right of } and press backspace, everything works fine.
Is this a known problem?