This is discussed earlier, but still not clear for me.
In the reference design AM335x industrial EVM (and others) there is an external LDO for VRTC which is sourced from the main power plug, not from Battery.
The Coinbattery is connected to the PMIC. What is this for, the RTC from the PMIC isn't used. The RTC in the AM335x is used and this one has no battery with this schematic.
So for me the Coin battery is useless.
And looking at the power sequence of the TPS65910A3 I don't see a problem.
Some people talk about the EXT_WAKEUP output of the AM335x. But this signal is an input !