Battery percentage has nothing to do with temperature. This can occur when the outside temps are quite high, and/or if you have not stored your battery properly before flight...eg. leaving the battery in a hot vehicle. You should not fly with overheating batteries. They will shut down at a certain point.
Depend on what you doing you could shorten flights a bit,I never fly full batt anymore cause Yeh does get bit warm,could do long reverse circles so air cools battery down a bit,,even the p4 ones get hot
1. High ambient temperature
2. Aggressive flying - lots of stop / starts and climb outs
3. Battery getting old or excessive periods of high charged state
They are just a few.
To correct a comment made earlier : Battery state of charge CAN affect temperature of a pack when in use. The reason is that it requires WATTS to fly and as the packs charge is consumed - the Voltage decreases ... to compensate and keep action continuous - the Amps increase. Amps increase is opposed by Internal Resistance - causing heat.
Simple maths :
Full charged pack at 17.4V ... lets say it needs 174W to hover = 10A
Strorage level pack at ~ 15V ... still requires 174W = 11.6A
That 1.6A increase may not seem much - but its enough if battery is already working hard. And note that is at storage charge level - NOT at the levels we can push packs down to.
What was the maximum battery temperature you recorded? I have had a maximum battery temperature of 152.5 degrees F in the Phoenix, Arizona, USA area. I did not get a warning and I have had many more flights on that battery and that P3P aircraft. I am just curious.