The diode in the charge circuit has the potential to confuse the peak detecting chargers.

You can get the field charger to put power back into the battery, however if the peak detection does not work because of the diode... you can damage the battery.

The diode can make the peak detection circuit think the battery has appx 1.2 v less in it than what it really has... or it can prevent the charger form detecting anything about the voltage. (depending on the peak detection circuit design.)

For this reason, it is advisable to not have that diode in the fast-charge circuit. That is why I say...pull the battery out and charge it completely disconnected from the TX when fast charging.

I always prefer to fail on the side of telling you something that will improve the probability that you will not damage your equipment, rather than give any unnecessary risk, even if it might be small. Especially when it is so easy to avoid the potential problem.