Montage render dropout after updating to 9.5.40 using Sonnox Suppressor

I suddenly get a dropout early in a rendered file if I use Sonnox Suppressor HR as a Montage Track plugin.
It’s the VST2 version of Sonnox Suppressor HR; I haven’t installed the VST3 version yet.
I don’t recall having this problem until quite recently; perhaps after I updated Wavelab from 9.5.?? (between 25 - 35) to 9.5.40, which I did on 1/23/2019; and I’ve used Sonnox Suppressor HR many times in Wavelab before with no apparent problems.
Odd bc this problem doesn’t seem latency related; changing the ASIO buffer size doesn’t make a difference (even to the max 4096 with my RME PCI Hammerfall based system), nor does changing any other setting in Wavelab or Windows 7. Also, I have no problem rendering Montages using other plugins with very high latency; I just rendered the same Montage using DMG Equilibrium EQ plugin in FIR mode with a 65536 impulse length, which produces around 743 ms of latency at 44.1 kHz, with no dropouts or other problems. The latency in the Montage Effects Window reported for the Sonnox Suppressor HR is 233 ms; smaller by about 1/3rd.
(I even doubled the impulse in the DMG Equilibrium to 128k and had no problems on playback, though I didn’t try to render a file at that setting).

I wonder if the corrections made in versions .30 & .35 (related to timing & high latency plugins) somehow messed up the proper processing of the Sonnox Suppressor:
9.5.35: PAR-3194 Rendering a clip, track or output in the Audio Montage with a high latency plugin that has been bypassed, no longer adds silence at the beginning of the file.
Ironically, I can bypass Sonnox Suppressor HR and get a good render; only when it is engaged, it causes a dropout in the beginning of the file, a little after the reported latency of all plugins combined (I haven’t confirmed this numerically yet, but two recent renders seem to bear this out).
The other fix was for release
9.5.30: PAR3089 The Master Section Level Meter is no longer out of sync with the audio playback when using high-latency Clip or Track effects in the Audio Montage.

Since 64 bit processing is now the default, maybe this plugin does not behave properly in this mode. Try to activate 32 bit processing for plugins, in the audio preferences.

I can say that, generally, Sonnox VST 2 versions do not behave well in my system. But all the VST 3 versions function perfectly.

I just reported this to Sonnox and I can also test it out soon.

Sonnox VST3 is actually relatively new and in my experience, the VST2 versions were always very solid.

It seems that Sonnox VST3 versions came out around the same time WaveLab added 64-bit floating point processing so maybe the solution here is to use the VST3 versions.

I haven’t noticed any issues like this but soon I’ll do some test renders that have audio through the last sample so make sure there are no dropouts.

What’s interesting is that of all the Sonnox plugins I have, the SurprEsser VST3 HR and LL are the only one showing as 32-bit floating point still. The normal SurprEsser VST3 is 64-bit floating point. Hmm.

See my above post but FWIW, I tried reproducing this with both clip and track plugins in the montage and I can’t. I used both VST3 and VST2 versions of SuprEsser.

That being said, with especially high latency/high CPU plugin chains, I have seen cases where both the playback and rendering can stutter or drop out at the very very end of the audio. It’s most obvious when you have audio that goes to the last sample but if you have a song or audio with a slow decay to silence, it’s easy to miss this problem.

I would update to the latest Sonnox versions and try VST3, and also see if you can trace it to JUST this plugin or if it’s just a result of high latency/high CPU plugin chains in general.

Just for the record. No issues with Sonnox Suppressor here, using VST3 64-bit version of the plugin and Wavelab 9.5 running with 64-bit precision.