During my last flight, I took off, and my battery was showing 94% on the app..   So i flew around a while with full control as usual..  Then I looked again at the battery indicator, say after 5/8 mins and it was till at 94%.    I was a bit concerned and checked to see I hadnt lost connection or anything or control, but everything seemed fine.  I decided to land anyway out of fear that the battery had a problem.

It just stayed at 94%

I then turned off the phantom and the conrtroller and restarted everything, and just took off, to see if the battery gave an acurate read.  It then marked 45% which was just about what I expected it to be.

Anyone ever experince anything similar?

Do I need to be concerned?

WOW.  Great question since the battery is the life of the P2.  I would be very concerned and I look forward to the informed responses.

One habit I was trying to get rid of was I tend to fly out and then back just so I can see the battery lights despite what the screen says.  Maybe I shouldn't try so hard to get rid of it.

I would be concerned.  First thing I would do is hook the quad to the computer with that battery installed and see if the Assist program reports any anomalies/problems. If not, second thing I would try is to completely discharge the battery (8%) and then fully charge it again.  Then see if you get the same response when flying.

Discharging to 8 % as ngrwise said is supposed to keep the battery level monitor calibrated.   Good suggestion to take it down to 8$ and then recharge fully ( after allowing it to cool).