Removed the outer cover to a 2 week old swarm and the inside/top of the Vivaldi board had numerous Argentine ants. The ants were feasting on bee larvae.
I believe they crawled thru the screen of the Vivaldi board and took larvae from the cells. Then traveled back up to the top. The bees couldn’t follow them thru the screen.
I replaced the Vivaldi board with a standard inner cover and spent 30 minutes squashing ants. Put some ant poison stakes around the block supports.
Will wage all out war tomorrow!