Ed S

They seem to have a bug, where the entire charging cycle will not "reset" untill the battery is discharged enough.
As you mentioned, it seems the PV charger doesn't have this bug, but the utility charger does.
Some Axperts have this bug with PV too. 

1. i have the inverter set to USE. 
2. only have essentials connected, i run from UTI from sunset to around 22:00. base loads that time is varying as the fridge goes on and off. but it consumes 6/7% per hour. solar assist helps me to maintain the battery. i choose to cycle the battery, as it makes space to harvest PV. the next day- i need to add another battery, as mine is fully charged by 10:00 in the morning already, and the PV system is then just idling. 
3. i set the float and bulk the same, as the float bug is a reality if your voltage doesnt go low enough, especially charging on PV. it only charges to float voltage. BUT, once the PV drops, it tops it off from Utility till it reaches the SOC maintainer. that is why i raised the float to where i want it to be.
the 3.4v resting voltage is exactly that. resting voltage. and what i have learned with the LiFePo4, Voltage doesnt tell you much.
i use to think my battery is almost empty after 4 hour load shedding, lights on, TV on. fridge running. till i fitted the Smart Shunt. then realized after a 4 hour outage, that my battery was still at least 50%. 

I would use li mode if it's available as it will not charge the battery all the time and so is more lithium friendly . 
I would then set bulk to 27.6v 

my previous inverter didnt have the bulk timed charge function. and the floating bug is pretty much in all the inverters/batteries that cant communicate. im not running  a big system. so i dont have to fast charge (less than 2 hours), so i set the bulk the same as float. 27.6 is safe. and its not in the upper curve of the voltage, so it wont run away with the PV system. 
i would not even use the equalization function, as i dont see the need for lithium. the esener battery BMS is apparently an active balancer, so it always balances. not only from a certain voltage. i cant give more details, as i have yet to open one to see. but i set my batteries to charge at 28.2v for 12 hours once a month. and it seems to be OK with that, lithium will only absort the power it needs, and you cant overcharge them, unless you over voltage them. do not charge them to the absolute max, and keep them there, they need to settle, otherwise it gets bloated and gas's
i do have PV on the roof yes, that charges and supports all the essentials the whole day, and at night i let the battery run down to 40% SOC by 06:00. which ever comes first, as PV starts producing from there, although not much, but has enough power left for another 4 hours untill either PV is enough, or Eskom is back online if its rainy. 
Solar assistant helps maintain the battery, has that function. so if the battery drains faster than the graph, it switches to grid untill everything catches up. i dont charge from Eskom at all. unless the weather is really bad. 
 
IF i had to install a system again, as an backup, or for someone else, and dont have the capability to read SOC, i would again set the bulk and float to 27.6. and forget about it. 
ill do some tests on a lower voltage for bulk and float, to see when the "floating bug" starts setting in. 

i use a Axpert type inverter. and the battery setting is on USE. as i can set the float and bulk to whatever i want. and the bulk does have the timed bulk charge function aswell (not the equalize charge function).
also no comms between inverter and battery.
 
i also had alot of questions, and sat with multimeters and and and for days and hours. 
so i just bought a Victron smart shunt and a Raspberry, in loaded Solar assist. yes there is still flaws. but atleast i can try resolve this myself while i am not home, as i work out of country for weeks at end. 
 
even after installing the monitoring stuff, giving me a better idea of what is going on, and and and. i still run it on 27.6v. of bulk and float. 
and i play around ever so often with different settings to see what effect it has. 
again, i cycle the battery daily, so it doesnt sit at 27.6v the whole day, probably for 4 hours or so, and then solar decreases to where it starts using battery again.

28.4 and you can ones a month bulk charge to 29v . 
27.2 to 27.4  float
23v to 24 cut of 
Are are safe volts that should not damage the cels and volts that I have been using for over an year . 
My esener always settles at night around 26.6v  as I only charge from solar . 
On my older inverter there were volts  difference between inverter and lithium more  like 1 volts when it was under high  load . But with the new inverter its closer .