[SOLVED] Weird stereo image behaviour as send-FX

[Niowiad]

Hello.
As I was experimenting with feedback loops, I started to test my plugins' behaviour in preserving the stereo image when used as send effects. I'm basically sending a mono audio track to an aux track containing the plugin I'm testing, then I'm panning the source track from one extreme to the other (100% left and 100% right) and see how it translates to the aux track.

Most plugins worked as expected, except for MUnison (which I own, terrific plugin ) and MTransformer (which I'm demoing and very interested in). These two show very weird/unwanted behaviour, either inverting the stereo image or only playing out of one channel when the source track reaches the point of being hard panned to the opposite channel (e.g. it behaves normally sweeping from from left to right, then when it gets to the point of being 100% right, it only plays out of the left channel)

Anyone else can test this out? I might be missing something, hopefully not too obvious.
I'm on REAPER 5.941/x64 -- Windows7

Thank you

[jmg8]

They are both spectral and have an option to process in either mid/side or left/right.
It is MS by default, so you could try disabling that option?

[Niowiad]

They are both spectral and have an option to process in either mid/side or left/right.
It is MS by default, so you could try disabling that option?

My savior

That explains why sound only came out of the left channel when the source was being hard panned to right.

I had the "SPECTRAL SETTINGS" menu collapsed and honestly never noticed it had M/S activated by default (not exactly sure why, either). Unchecking that easily solved the issue.

Thank you so much