Mavericks
Nuendo 6.5.20 Build 174
If you hit the “Bypass all Inserts” button it works as expected.
Hit it again and it toggles them back to active.
BUT if the plug-in on slot1 is one that can’t be loaded f.e “!!! MonoDelay” all the following plugins on slot 2, slot 3 … don’t toggle back to active but stay in bypass mode.