Earlier today, On Tue, 20 Sep 2011, I wrote:
> It is not sensible to check for (*THEN) at run-time every time a group
> is entered. However, what I suppose I could do is to remember if (*THEN)
> is used anywhere in the pattern. If it is not, the old code could be used
> instead. I will see if this patch-up is possible.
This turned out to be quite simple. I have committed patches that
restore the old behaviour in cases where the pattern does not contain
(*THEN) anywhere. This should fix all your examples.
In future it might be possible to improve this so that it can check
groups on a case-by-case basis, but I am not sure whether this is
actually worth doing.
