newbie question about git push

Hi,

Apologies in advance if this has been covered before ... I've been 
wading through the archives a bit and couldn't find anything that seemed 
to address this basic question.

I have a bunch of machines I use for development, but only one of them 
is allowed to connect via vpn to where the subversion repository lives, 
so I'm using git-svn to make things a little easier.

I've got one machine, itchy, where I've done a git svn clone operation.  
I do a fair amount of development work there, and typically I just work 
on the master branch, and periodically commit back to svn using git svn 
dcommit.

I've cloned the repository on itchy on a few other machines I 
occasionally use, and I'm able to push new revisions from itchy with no 
surprises, and I can pull revisions back to itchy ok with no surprises.

Where things get a weird is when I push a revision back to itchy from 
one of my other clones.  I feel like I must be missing some fundamental 
concept, and I'm wondering if someone can help.

Suppose I make a change on another machine commit that change, then push 
it back to itchy:

git commit -as
git push origin master

This works ok, and I can then git svn dcommit that change back to the 
svn.  But I have a hard time getting that change to show up in the 
sandbox I have on itchy.

When I go back to itchy after pushing from a satellite, git thinks that 
the old revision of the file I modified on another machine, has been 
modified locally; it doesn't see that the local copy is out of data and 
this new revision needs to be merged.  But I can't figure out how to get 
git to do that; the only things that seem to work are fairly drastic 
measures,  like "git reset --hard" or by stashing and then deleting the 
stash. Either seems terribly error prone.

I'm starting to think that I should clone the repo I cloned from svn for 
doing development work on itchy, but this seems kind of wasteful.  Am I 
missing some fundamental concept?

Many thanks for any thoughts.

cheers,
Eric