TP4056 and li ion battery charging that never ends
The charger is probably acting as intended.
By drawing power from the battery after charging completes you are discharging it and causing the voltage to drop to the recharge point.
This is bad for battery cycle life.

The solution is to arrange battery and the charging source in such a way that the circuit draws energy preferentially from the power supply when it is on.
If you are supplying 3V3 to the circuitry then presumably you have a regulator between the battery and the 3V3 bus. The regulator may be on the node mcu pcba. Or not.

The simplest sharing circuit is to provide diodes from battery and power supply to the voltage regulator input. The maximum Vbat = 4.2V. If Vpsu > 4.2V the circuitry will be operated by the psu. When mains power is removed the battery takes over.
The battery to vreg diode should be a Schottky diode. The psu to vreg diode can be Schottky if desired but an eg 1N400x will suffice.

This site has a number of questions related to backup supplies and these will provide other means of supplying the vreg from the battery with minimal Vdrop. (A MOSFET is often used).