Very Computer

I've had a look in the FAQ and in deja to no avail, so I'll try here. We're
running AIX 4.3.3 - suspiciously we've just added a load of patches and done a
reboot. Logging in is fine, but when we do a switch user it appears that
/etc/environment is not being used, *but* if we then do another su it *is* being
read, another one and it isn't, weird huh? For example:

/home/chall > grep DOC /etc/environment
DOCUMENT_SERVER_MACHINE_NAME=localhost
DOCUMENT_SERVER_PORT=49213
DOCUMENT_DIRECTORY=/usr/docsearch/html

/home/chall > set | grep DOC
DOCUMENT_DIRECTORY=/usr/docsearch/html
DOCUMENT_SERVER_MACHINE_NAME=localhost
DOCUMENT_SERVER_PORT=49213

/home/chall > su - chall
Passwd:

/home/chall > set | grep DOC
                                  <--- No output
/home/chall > su - chall
Passwd:

/home/chall > set | grep DOC
DOCUMENT_DIRECTORY=/usr/docsearch/html
DOCUMENT_SERVER_MACHINE_NAME=localhost
DOCUMENT_SERVER_PORT=49213

/home/chall > su - chall
Passwd:

/home/chall > set | grep DOC
                                  <--- No output
/home/chall >

Anybody got any idea about this?

Thanks in advance
Chris.