Plug-ins on the Stereo Out blocking audio

I just discovered that a project I’ve saved with active insert effects/channel strip effects on the Stereo Out will be silent when re-opened.
Meters are showing activity on the tracks but not on the Stereo Out. That is until I bypass/remove the insert effects and channel strip effects. Only then could I get sound. I don’t know if this is a general problem or only with the project I’ve been working on today, which is the first since installing 9.5.1.

Anyone else?