The reason for the crash is that JUCE used to return an AudioEffectDefinition that was allocated on the stack, so when Unity tries to access it causes undefined behaviour.
Anaglyph framework is using an older JUCE framework which is causing this crash in Unity 6, updating to JUCE framework 8.0.6 or later in Anaglyph plugin will fix this issue.
JUCE commit: https://github.com/juce-framework/JUCE/commit/c51bfd7429775c5ff8d09a0cb58ed4b71f6eba93