[bug-grep] 'grep -F -w' fails to find certain matches

[vpefimov-sf]

'grep -F -w' misses matches if they are preceded by a
non-word match. I get this on Windows 2000 with two
different grep binaries and on Linux (Puppy Linux live
CD):

C:\>echo PATTERN7 PATTERN | grep -F -w -c "PATTERN"
0

C:\>echo 7PATTERN PATTERN | grep -F -w -c "PATTERN"
1

C:\>grep --version
grep (GNU grep) 2.5.1

Copyright 1988, 1992-1999, 2000, 2001 Free Software
Foundation, Inc.
This is free software; see the source for copying
conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE.

C:\>

Is this a bug?