strange sendmail problem after upgrading to Tru64 Unix V5.1B pk5

We just upgraded our Tru64 Unix from V5.1A to V5.1B pk5. Everything went
fine, with one quirk.

We have a sendmail alias set up to run a perl script for any inbound
e-mails to a particular account. After the upgrade, this stopped
working.

The specific directory path to the script is ~vlink/Script/myscript.pl.
As anyone knows who has tried troubleshooting these types of problems,
it's a real pain. But the light bulb finally went off when I tried
sending an e-mail locally on the machine to this account and I got
additional information. The message was that it couldn't find the
directory ~vlink/script/myscript.pl. (Note the changing of the
case-sensitivity from /Script to /script.)

I got it working by renaming the directory from /Script to /script, but
this seems really odd to me! Definitely the aliases file has not been
changed, and it's using the /Script directory (upper-case).

Anyone have a clue what's going on? The sendmail we're running after the
upgrade is 8.11.1. I'm not sure if, during the Tru64 upgrade, if it also
upgraded sendmail. I wouldn't have thought this would happen, but could
be wrong!

Thanks and regards,

Chris