Cronus is main V-Vocal dll. This is disabled on install because V-Vocal is not intended to show up in the list of available plug-ins. In CbB it appears as a Region FX. There is no reason to enable the dll. V-Vocal is not a regular DX plug-in. V-Vocal works with Cronus disabled in the Plug-in Manager.
The scan toast appears based on settings in preferences. Regardless, the scanner is for VST plug-ins only.
The project load toast was added in CbB 2018-07.
The age of the project does not matter. The age of the plug-in does. V-Vocal has not been updated in years and was last bundled with X2.
Not sure why a project would try to load Cronus if all V-Vocal clips were rendered. Maybe not all the clips are rendered. Safe mode may help. When loading a project in safe mode there is a prompt to load Cronus along with the clip name for each unrendered V-Vocal clip, however; there is no prompt to load Cronus if all clips are rendered.