On mIRC 6.16, Windows XP

In older versions of mIRC where certain expressions testing certain strings would cause it to hang for a while but still return a correct result, on 6.16 it seems to "give up" after about 1.3 seconds (on my machine) and return a value of -8

Code:
//echo -a $regex($str(1,30),(\d.*){30})


Of course the workaround in this particular case is $iif($regex($str(1,30),/\d/g) > 29,1,0) but it's just an example

Could this be intended behavior, returning -8 rather than hang for an unwanted amount of time? The change isn't mentioned in versions.txt so it wouldn't appear so. The same behavior is seen when using $regsub