[UNITY, FMOD] Reverb Plugin Grayed-Out in Reverb Mixer Bus

[bytecauldron]

System Information

• Steam Audio version: 4.5.3
• FMOD Studio version: 2.02.23
• Unity version: 2021.3.33f1
• Operating System and version: Windows 10 22H2

Issue Description
Hello! I'm not entirely sure what can be done about this for the time being because it's mainly an FMOD Studio issue, but I wanted to pass it along. They have been aware of it for the last few months and the fix isn't in stable yet. This appears to affect the Steam Audio Reverb plugin when attempting to add it to the mixer's reverb route.
https://qa.fmod.com/t/plugins-greyed-out-on-groups-master-bus-2-03-02/21945
They were trying to add something to the master route in that thread, but it looks like reverb is affected as well. Plugins are grayed out where they shouldn't be.

Steps To Reproduce
Steps to reproduce the behavior:

1. Download the latest stable version of FMOD Studio (Unity Verified).
2. Create a FMOD studio project and follow the Steam Audio Documentation to add the respective plugins. (In my case, I used the Windows x64 option).
3. Try adding the Steam Audio Reverb plugin to the mixers reverb route return following the provided docs.

Here it is grayed out in the mixer's reverb route (from 2.02.23):

This is what it's supposed to look like (from 2.02.21):

Using a previous version like v2.02.21 seems to fix this. You "can" add the Steam Reverb plugin if you first add it to an event, and then copy/paste it into the Reverb route, but this doesn't seem to have an effect at runtime in Unity from my experience.

Let me know if you need any additional information. Thank you!