grep: different results between Version 2.5.1 and 2.5.1a

[Roman Berger]

Hello,
 
I'm using Win32 grep with the Perl regular expressions, I updated from the grep 
version 2.5.1 to 2.5.1a and I get a different result with the newer version:
 
Example:
 
SourceFile.txt
LineA
LineB
LineC
LineD
 
RegexFíle.txt
(?:LineA)|(?:Line(?:(B|C|D)))
 
Command:
grep.exe -P -U -i -f RegexFile.txt SourceFile.txt
 
Result with grep version 2.5.1:
LineA
LineB
LineC
LineD
 
Result with grep version 2.5.1a:
LineA
LineD
 
I attatch both versions to see which dll I'm using.
Do you know about this behavior?
Is a fix planned?
 
Best regards
Roman Berger