Error not passed as query string when using custom error page

[0x6c23]

Description 🐜

When I specify a path as custom error page it will resolve to ?error=undefined#
When I don't use the option it passes the correct error code.

Using version 4.0.0-beta.6

Is this a bug in your own project?

No

How to reproduce ☕️

pages: { error: "/signin", // Error code passed in query string as ?error= },

Screenshots / Logs 📽

No response

Environment 🖥

System:
OS: Windows 10 10.0.19043
CPU: (12) x64 Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz
Memory: 15.81 GB / 31.93 GB
Binaries:
Node: 14.17.6 - C:\Program Files\nodejs\node.EXE
Yarn: 1.22.10 - ~\AppData\Roaming\npm\yarn.CMD
npm: 6.14.15 - C:\Program Files\nodejs\npm.CMD
Browsers:
Edge: Spartan (44.19041.1266.0), Chromium (95.0.1020.53)
Internet Explorer: 11.0.19041.1202
npmPackages:
next: 12.0.1 => 12.0.1
next-auth: 4.0.0-beta.6 => 4.0.0-beta.6
react: 17.0.2 => 17.0.2

Contributing 🙌🏽

No, I am afraid I cannot help regarding this

[0x6c23]

So sorry, didn't see it! Possible duplicate of #31

[0x6c23]

Closing already fixed in #3141