Interesting, as I was about to present the same type of question to the forum board when I noticed your posting, WebMaxiumus.
I too believe this issue is related to the battery, however while I personally have encountered a brief sounding from the battery alarm, I had noted the battery level at over 85%, and was able to continue flying until the battery voltage indicated 30% which is when I usually begin to land. As mentioned the alarm sounded for only a brief moment.
I noted this sort of issue had occurred on two separate occasions using batteries on two different phantoms ( a Vision, & Vision Plus ). I will certainly look to determine if there is any variation between the cells on each of the batteries used.
One of the units was still using the older firmware 3.0, so it really had nothing to do with the different updated aspects between F/W 3.0. and newer version F/W 3.06, but more so to one of the batteries, were my thoughts.
POI, all my batteries have a round contact spot within the face of the battery, but I do ensure both the contacts on the battery, and contact pins within the Phantom are clean and working as they should.
As an update to my original comment, I have since checked the cells on both batteries I've been using and have not found any discernable variation between any of the batteries cells. Maybe all a coincidence, or maybe NOT!