Hey there, I've been using Reaper for years now and I feel a little ashamed that my first post here is a Bug report. But it is what it is.
I do experience the same things like Tomer does. I try to explain as clear as possible and to narrow down the possibilities causing that.
I put a project of a metal production into apples iCloud to make sure I open the exact same project on different Machines.
Reaper v6.46
Plugins in use:
Neural DSP Darkglass Ultra, Archetype Nolly
Brainworks bx_Solo
Waves SSL EV2
FabFilter Pro-Q3, Timeless 3
Valhalla FreqEcho, SpaceModulator, Shimmer
HOFA IQ-Comp, IQ-Limiter, IQ-Analyser, IQ-DeEsser, IQ-Reverb
All installed plugins a 64bit and the newest version. All Plugins are VST3.
When I load it on my MacBook Air M1 MacOS 12.1 Monterey there appears an icon named: "reaper_host_x86_64" in the bay and stays there. And some of the Plugins are named "Plugin Name (x86_64)" others are normal. You can see it in picture 1, wich is a screenshot of my desktop.
Reaper is loading very slowly and sometimes the "reaper_host_x86_64" crashes and audio from tracks with related Plugins ist not played anymore. Occasionally as mentioned by Tomer the gui is not loading these plugins.
Opened the project on my colleges MacBook Air M1, with exact same specs and exact same plugins and versions installed causes same behavior.
Opening the Project on my iMac i7 MacOs 11.6 BigSur: Reaper loading fast as usual, no "reaper_host_x86_64" and everything does what it should do. As shown in picture 2.
For my understanding: ist that x86_64 the also called "bridge mode" for using 32bit Plugins in 64bit environment? If that is the case, Reaper is falsely detecting 64bit Plugins as 32bit versions, on M1 systems or on MacOS 12.1 Monterey or in combination.
If I open an empty project on the M1 the "reaper_host_x86_64" icon does not show up. When I add plugins that performed normal in the other project ist still does not show up. I loads when I add things like the SSL EV2 or the Neural DSP Archetype Nolly or others.
I hope this might help to trace down the source of that problem because it really affects the usability of reaper when using M1 systems. I never experienced reaper behaving slow unexpected and buggy like this. And I want it to be reliable again, because IMO it ist the fastest and most flexible and also stable DAW out there.
PS: I can not upload the pictures because of a "security Token is missing". If of interest please tell me where to mail those.