ParenMatch is indeed failing when the cursor is after the first parenthesis of the following code:

(3 +
 4 - 1)

This happens both in Shell and Editor windows.

I've traced the problem down to HyperParser. It doesn't properly support multi-line statements, as can be seen by the following line in HyperParser.__init__():

stopatindex = "%d.end" % lno

(this appears twice, once in each branch of the same if statement)

Fixing this requires looking forward a few lines to find the end of the statement. I'm continuing to look through the code to try to find an efficient way to do this (without parsing the entire file).