I thought I was going crazy, but I eventually caught it.

Having just installed the i386 1.1 binary snapshot from wasabi on my
notebook, I was sync'ing the machine with the config tree (which made
it quite simple to get the box up and fully configured again).

I noted that sync_tree claimed lots of files which had just been
installed from the config tree we different on the machine.  I knew
this was not the case and md5'ing both files verified it.

When I ran the script again, a different set of files were claimed to
be different.  I eventually caught it in the act.

+ md5 /etc/shells
+ set -- MD5 (/etc/shells) = 6b034f83536f7478368b3838c3b4e7ac
+ eval echo $4
+ echo 6b034f83536f7478368b3838c3b4e7ac
+ dest_sum=6b034f83536f7478368b3838c3b4e7ac

...

+ md5 /mnt/configs/local/not/etc/shells
+ set -- MD5 (/mnt/configs/local/not/etc/shells) = 6b034f83536f7478368b3838c3b4e
7ac
+ eval echo $4
+ echo 6b034f83536f7478368b3838c3b4e7ac
+ src_sum=6b034f83536f7478368b3838c3b4e7ac

+ [ 6b034f83536f7478368b3838c3b4e7ac != 6b034f83536f7478368b3838c3b4e7ac ]
+ [ yes ]
+ echo  - Changed

The test of [ 6b034f83536f7478368b3838c3b4e7ac !=
6b034f83536f7478368b3838c3b4e7ac ] is being evaluated incorrectly. But
only occasionally. 

The shell being used was /bin/sh so if '[' is a builin its a sh bug
otherwise its /bin/test

I'll have a look once I've had a chance to unpack the tar_files.

--sjg