Blue Ripple Sound plugins stopped working between 13.0.9 and 13.0.10
Blue Ripple Sound plugins no longer show up after "Scan for Plugin-Ins" from 13.0.10 onwards. They should!
Debugging shows that Audition does scan through the plugin libraries to retrieve the plugin details, but it then doesn't show them.
If the scan is done using 13.0.9 the plugins are then usable in 13.0.10 - until "Scan for Plugins" is used, at which point they disappear.
This problem also affects Premiere.
I am one of the plugin developers and keen to get this sorted. Please contact Blue Ripple Sound if we can help debug this as we are very keen to get it sorted out!

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Richard Furse commented
The corresponding break in Premiere appears to be between 14.3.2 and 14.4.
Note that these are VST2 shell plugins.