AudioStreamPlaybackPolyphonic: streams with id > 1 cannot be stopped or changed

[xerothermic06]

Tested versions

Reproducible in: 4.2.rc

System information

Godot v4.2.rc (1ba920f) - Windows 10.0.22621 - Vulkan (Forward+) - dedicated GeForce RTX 2070 SUPER () - Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz (16 Threads)

Issue description

AudioStreamPlaybackPolyphonic can play more than one stream, but all streams after the first one cannot be stopped or modulated. The is_stream_playing method returns false even when streams are audible.

Steps to reproduce

• invoke play() on an AudioStreamPlayer node that has an AudioStreamPolyphonic
• invoke get_stream_playback() and use play_stream() to play multiple audio streams
• invoke is_stream_playing on the IDs returned from play_stream()

Minimal reproduction project (MRP)

polyphonic_test.zip