BUG DESCRIPTION:
After reopening a Nuendo project, some instances of Slapper appear to be active but produce no audio.
The plugin GUI works normally, meters move, delay taps are visible, and it seems to receive and process signal, yet no sound is heard.
Duplicating the Slapper instance within the same FX channel immediately restores the audio output.
Once duplicated, the new instance behaves normally until the next session reopen, when the issue reappears in the same way.
SYSTEM SPEC Slapper 3.0.19, MacOS Venutra 13.7.8, Nuedno 13.0.55
STEPS TO REPRODUCE: The issue occurs sporadically. The issue seems to occur sooner or later when using Slapper (VST3) in Nuendo on FX channels.
There’s no specific action that triggers it consistently, not that I’m aware.
NOTES (detail on variations, intermittent behaviour etc):
The issue affects the first Slapper instance in the mixer from the left, regardless of which FX channel it’s on.
It looks like the first Slapper instance created when a project is loaded fails to initialise its audio engine properly — the GUI is active and shows meter movement, but no audio is heard.
All subsequent Slapper instances work normally.
As a workaround, I created a hidden FX channel named “BUG SLAPPER” with a bypassed Slapper instance placed at the far left of the mixer.
That first “sacrificial” instance always stays silent after reopening the project, but every other Slapper instance loads and works reliably.
The workaround has proven 100 % effective so far, even across multiple reopenings of the same session.
However, I’ve noticed that the problem can also occur in other positions if audio tracks are placed between FX channels.
My template is structured like this:
dialogue audio tracks → dialogue FX channel,
SFX audio tracks → SFX FX channel,
music audio tracks → music FX channel, and so on.
Even with the dummy “BUG SLAPPER” instance protecting the dialogue section, I had to create an additional dummy FX channel for the SFX group — it seems that when audio tracks are interleaved between FX channels, Nuendo may re-initialise the Slapper instances in a different order.
In those cases, the first Slapper encountered by Nuendo’s initialisation sequence (not necessarily the one furthest left in the mixer) becomes the silent one.
This suggests that the bug is linked not only to the mixer order but also to Nuendo’s internal track-initialisation sequence, which changes depending on the project layout and the presence of interleaved audio tracks.
If it helps, I’m happy to share my Nuendo template (without the dummy tracks) so you can test the behaviour directly.