There seems to be a memory leak somewhere (maybe not technically a 'memory leak' since you are using Python but), phoenix uses several hundred megabytes of ram after several days of running. My guess is a failure to prune some sort of list of completed shares / console output / something. I would simply quit and restart, but I've run into the previously mentioned bug where my normally stable system would completely freeze upon exiting phoenix. This one I can't seem to reliably reproduce, it happens sometimes upon exiting but most of the time it's fine.
I have had that lockup issue for a long time and I think I just found a way arround it. I am guessing your using Ati11.4/.5? If so try 11.3. Have two machines that were having this issue with 11.4 and it has cleared up with 11.3. That bug is realy bad on a non dedicated miner..(other stuff has gotten corrupt for me because of lockups from loosing the app close russian rullett)