%scan BIF error or not?

["Brad Stone" <brad@xxxxxxxxxxxx>]

I've encountered an error on a V4R5 machine with the %scan
bif that doesn't appear to happen on V5R2 and functions as
I would assume it would.

Here's the example:
eval string = 'thisisatest'
eval j = %scan('test':string:10)

Notice that the start position plus (10) the length of the
lookup string (4) is longer than the string I am scanning
(11) (this is where the problem seems to lie)

Now, I get the following error on V4R5:
Length or start position is out of range for the string
operation.

In V5R2 I simply get 0 for j and things work fine which is
how I assumed it would work.  

I have made sure the starting position isn't more than the
length of the string being scanned... it seems when the
starting position plus the length of the lookup string is
longer than the string to scan it throws this error.

Is this correct behavior, or is the behavior from V5R2
correct?  If V5R2 is correct, is there a PTF to fix V4R5?