bug: limit-conn，After limiting concurrency for the first time, all subsequent requests are blocked

[y934317258]

Issue description

limit-conn，After limiting concurrency for the first time, all subsequent requests are blocked

Environment

• apisix version (cmd: apisix version):master
• OS:centOs

Minimal test code / Steps to reproduce the issue

1.config

2.first.it's true

3.then,error occur

What's the actual result? (including assertion message & call stack if applicable)

After limiting concurrency for the first time, all subsequent requests are blocked

What's the expected result?

like first

[moonming]

Can you provide reproduction steps using admin API? @y934317258 thx

[spacewander]

Closed as lack of response.