Why do the cashier apps of major banks not receive voice broadcasts when they exit the background, but receive them through WeChat?

Because the voice broadcast function is not turned on in the software.

If there is no voice broadcast on the receipt code of Agricultural Bank of China, it means that you have not opened the broadcast suite. As long as you open the radio suite, there will be a voice broadcast. This can be done by yourself on the mobile phone, and it doesn't cost much money and it's not too much trouble. Just follow the prompts in the system step by step.

The Agricultural Bank of China has no right to say about the collection, because the system is not set. If there is a voice setting, it will appear. If there is no voice setting, it will not appear. It has nothing to do with any bank. The same is true of Agricultural Bank of China, including other banks. Without voice, the collection will not be affected.