Your code both registers the on_conv_done callback and tries a polling read with 0 timeout. Not completely sure on this, but I'd expect the driver to consider the available data consumed when the callback returns.
Try 1. not registering a callback and 2. calling adc_continuous_read() with a ...

In the official example I only modified the channel array, which should have been channels 8 and 9, and channels 0 and 1 when printing the result.

The code is as follows：
/*
* SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0 ...

When using ADC1:
① When I configure reading the raw data of ADC_CHANNEL_3, ADC_CHANNEL_4, ADC_CHANNEL_5, ADC_CHANNEL_6, the readings are normal;
② When I configure reading the raw data of ADC_CHANNEL_2, ADC_CHANNEL_7, ADC_CHANNEL_8, ADC_CHANNEL_9, there is an initial value in the first ADC_CHANNEL ...

同其他通道一样进行配置，结果通道2上电就有读数，然后通道8和9输入模拟信号读不到数据是怎么回事，其他通道，例如3、4、5、6、7就可以正常读数。
有大佬可以解疑嘛？十分感谢！
环境：VSCode + IDF 5.2.2