I have had problems with subwoofers and satelletites. As fast as any stereo chorus is kicked in the subwoofer disappears, with no bass. The swriling occurs in the sattelites only and the resulting sound is to thin, combfilter and crossover effects, i e just the high treble and high mid are heard.
Fake stereo in my opinion is what most early digital 80s reverbs, chorus, and delay had:
If you sum them up with the balance knob and sum the left and right into one single MONO channel and the signal will disappear entirely. If it was "real stereo" you should be able to sum them up in mono and still be able to hear them. I remember blockbuster hits of the 80s heard on the radio and as fast you had mono radio or something like that, you heard that something just sounded out of tune with pitch wavering. And some freqencies lost. I think it was some Roxette hit, but I can't remember. Sounded like "zero through" flanging but wasn't zero through flanging. Now we're getting deep. But all things disappeared because they used phase shift. But their take was : "Who's listening to mono these days?"
We have also those reverb algorithms and manufacturers who make shortcuts onto their reverbs when making "true" stereo. Digital delays just stuck on top of each other. And we have manufacturers with cocky attitudes who claims that just their own gear are true stereo reverbs, and can't even be made a copy of with convolution reverbs as IRs and so on. It's not Bricasti, Lexicon, or anyone else known, but small German boutique manufacturer Q.R.S who makes over the top expensive hardware units. Quantec Room Simulator. They have a funny and peculiar warranty policy: 30 years. That's why they make sure they're expensive so it will have insurance so the company will not go bankrupt. You can't still use them on bass though, and you shouldn't.
But mainly it is about this: the Cologne Dome Cathedral has a reverb when you're inside it. It has sounded like that for 300 years, and will do so for another 300 years. The acoustics are the same. And yes, it's in stereo... if you clap your hands or yell in there...

No phase anomalies anywhere. SOB everything's real!
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Tip: Don't use these BOSE systems to think you can get stereo by just spreading it around with that "pipe" speaker.