Is it OK to associate 1 wireless bridge to 2 APs?

[kitepilot at kitepilot.com]

Hello there:
This question makes many assumptions, most of which I have no real knowledge 
of, so feel free to jump at any statement. 

I have a "tree" of APs all with the same ESSID.  The reasons, valid or 
invalid, are beyond the scope of the question, but feel free to challenge 
the wisdom...   :)
Long story short, I'm ditching the whole idea, but that's another post. 

The issue is that I can see the MAC address of one client,
registered in the arp table (associated) to 2 different APs SIMULTANEOUSLY. 

Now, the question is:
Is it OK for a bridge to associate to 2 APs simultaneously?
Is that reflecting other problems?
Will it become a performance issue (loop)?
THANKS!
Enrique