ADC LN-02 (LN882HK) board always reads 820..840 on PIN0

[deadphreaker]

Describe the bug
When configure PIN0 as Btn external input with 10k resistor pull-up works fine.
When configure PIN0 as ADC (A0 pin in LN-02 pin description this is ADC2 channel) it always reads 820..840 even if it grounded and actual voltage on PIN0 is 0v.

Firmware:

• Version: 1.18.109
• Device: Elivco Cozylife 16A Mini Switch
• Chip/model: LN882HKI, LN-02 module, model RMW002
• Device config
  {
  "vendor": "Tuya",
  "bDetailed": "0",
  "name": "Full Device Name Here",
  "model": "enter short model name here",
  "chip": "LN882H",
  "board": "TODO",
  "flags": "1026",
  "keywords": [
  "TODO",
  "TODO",
  "TODO"
  ],
  "pins": {
  "0": "ADC;1",
  "1": "Rel;0",
  "19": "LED_n;0",
  "24": "Btn;0"
  },
  "command": "",
  "image": "https://obrazki.elektroda.pl/YOUR_IMAGE.jpg",
  "wiki": "https://www.elektroda.com/rtvforum/topic_YOUR_TOPIC.html"
  }

To Reproduce
Steps to reproduce the behavior:

1. Go to 'PIN SETTINGS'
2. PIN 0 set as ADC on channel 1
3. short S1 and S2 terminal (pin 0 will get a 0v level)
4. See readings in channel 1 = 820...840 at device's web interface

Screenshots
If applicable, add screenshots to help explain your problem.

Additional context
Looks like ADC readings are from wrong pin number instead pin 0