Had this problem with some of Boz's VST3 plugs.. Manic Compressor for one....(and used the VST2 version), but that eventually corrected itself with various updates over time.  I guess since the new Adaptive Limiter does not have a VST2 version, I'm outta luck for now.  No idea why this happens or did in the past.
Anyone else experience this?  Also in "idle"...the meters are going as well showing some kind of input....if that's what those on the right side are supposed to do.

ah...turning OFF MSCSS seemed to be a fix.  ;-)

btw, I'll be interested in hearing what others think, keeping this as transparent as possible and just cutting off some nasty peaks...very minimal brick walling...
This'd be great in the PC. (I guess use FX chain).  Have to make the FX bin "post" I guess??

mixmkr
ah...turning OFF MSCSS seemed to be a fix.  ;-)

that's interesting ... are you sure this fixed it or something else that was changed at the same time???

That was the fix. Back on problem returns

Mixmkr,
 
I think I am seeing some of the same symptoms with the Adaptive Limiter as you were. I'd like to try your solution, but what is MSCSS? Any input would be greatly appreciated!

MMCSS
Go to preferences>settings>audio... and uncheck box if checked.  The option is fairly new I believe, geared for laptops or whatever...since I don't really know what I'm talking about!

Thanks, Mixmkr, I'll give it a try and let you know what happens!

Well, unchecking MMCSS did not make any difference for me.
 
In one project, adding the adaptive limiter to the master buss gives the "ring modulator" type of effect when the project is playing, and the meters on the right hand side are active even when the project isn't playing.
 
In a couple other projects, adding the adaptive limiter to the master buss results in a constant approximately 700hz tone that registers +9db on the master buss meters as soon as playback is started. The audio of the project itself does not play, only the 700hz tone, and it does not stop when playback is stopped. The only way to stop it is to bypass the plugin. I'm glad I wasn't using my monitors or wearing my headphones when testing this, or something might have blown!
 
I tried the other Platinum supplied limiters and IK Tracks Brickwall Limiter, all of them work as expected when added to the project. I'm at a loss as to what is happening.
 
I'm using the latest version of Platinum, Windows 10, an I7 4770k processor and a Focusrite Saffire Pro 40 interface.

bummer  This has only happened with VST3 fx for me.   If there was a VST2 version, it always worked and was my workaround, mentioned above.  I'll try some more experimenting too.