[Bug]

### Contact Information

{"a":"123","b":null} 这样一个情况就把聊天界面拉崩了

### MaxKB Version

都会这样

### Problem Description

{"a":"123","b":null} 这样一个情况就把聊天界面拉崩了

### Steps to Reproduce

{"a":"123","b":null} 这样一个情况就把聊天界面拉崩了

### The expected correct result

_No response_

### Related log output

```shell

```

### Additional Information

_No response_