Deeds - Warranty: Can a General Warranty be Subject to Adverse Conveyance

My question involves real estate located in the State of: Virginia

Can a general warranty deed be subject to adverse conveyances?

The language on the deed states "This deed is made subject to any and all .... adverse conveyances"

wouldn't the implied covenant that the land is "free of encumbrances" prevent this?

Deeds - Warranty: Can a General Warranty be Subject to Adverse Conveyance