CHRG pin behaviour when the battery is quite charged

Hello,

In my system, I use the CHRG pin to check whether my custom board is placed on the charger. The CHRG pin is directly connected to a microcontroller through this circuit:

I use R5 and R6 to decode all the CHRG pin states, particularly high impedance and pull-down.

When the battery is nearly fully charged (approximately 4.19V), the charge pin (CHRG_BAT) sometimes goes high. In my circuit, a high state on the CHRG_BAT pin indicates a high impedance state, meaning there is no input power. This situation occurs while the transmitter is searching. Below are some images showing the CHRG line (in purple) and Vfb (in yellow).

Sometimes, the CHRG pin initiates the Blink Slow state, even if the two coils are not matched. During the search, the pin enters a high-impedance state, here is an image:

According to the datasheet, the CHRG pin should remain in a pull-down state when the End of Charge C/10 is reached, or when charging is complete; however, this does not seem to occur.

Thank you