Broken undo history with Multi Delay device

[Splines]

Bug description

In a test project, I recently noticed how the Undo history was broken. I don't know how I arrived at this state. The undo history somehow stopped working at some point. It only shows: Undo Change in "E4L Multi-Delay" and nothing happens when clicking on it. This behavior stays the same even if you perform an action, e.g. turning on/off a track. It also stays the same even if you perform an action in the E4L Multi-Delay device.

Except for the Undo history, everything else seems to work just fine, e.g. audio playback. Parameters in the E4L Multi-Delay device can also still be adjusted and affect the sound. It's just that I can't undo anything in the whole project anymore (which makes it practically unusable).

Project file

I stripped down everything to the bare bones and only two tracks are left now:

• one Midi track that has the audio device, then an E4L Stereo Panner, then an E4L Multi-Delay and finally an LFO on it
• one E4L Master track with nothing but the E4L Master Bus device on it

You can download the project file here (I will try to make sure the link is valid for at least 1 month).

Ger a working undo history again

Delete either the LFO or the E4L Multi-Delay device. After that, the version history is working again as expected. E.g. turn on/off a track and it will show up as undo event.

System

• Ableton Live 12.0.20 (Suite)
• Windows 10 Version 22H2: I know that EnvelopSound is not officially supported for Windows, but maybe there's still a fix for this ;)
• Envelop for Live 12.0.5