Well, there is 1 more way a system having the VFF 30 filter lock might flood an engine while the engine is at rest (not running).
This would occur more on filter locks that have a lot of age/use on them.
If the vacuum diaphragm has a pinhole perforation in it........fuel can travel from the filter side of the VFF 30 past the operating pin seal and then make its way through the diaphragm perforation and ultimately reach the engine via the filter lock vacuum hose.
Have seen this a few times. Test it by soapy water applied to the open end of the VFF 30 vacuum hose nipple immediately after turning off the engine. If you observe any bubbling at all the VFF operating diaphragm has a perforation in it as well as excessive wear to other internal parts of the VFF 30.