[QUESTION] 项目中之前使用的是1.2.83升到2.0.64 应用报个nacos错误

项目中之前使用的是1.2.83，现在要求修复漏洞我升到2.0.64。升级后有一个应用开始报错如下图：
我是两个应用，有一个不报错，有一个报错。nacos client的版本相同时1.2.1，无法升级更高的版本，因为改动太大。
我认为还是2.x版本对1.x的fastapi兼容方面有bug。麻烦看一下，

Start by comparing the two applications and their upgrade configuration, then reproduce the failure when moving from 1.2.83 to 2.0.64 while retaining nacos client 1.2.1. Use the attached error image and comment thread to identify the failing compatibility path; done means the failing application works without the error or the incompatibility is clearly confirmed and documented.

Written by the indexing model from the issue text.