Cannot open Hello Neighbor Alpha 4 umap packaged with 4.15

[SospectGuy58]

Hello, I am trying to open this umap packaged with 4.15 using the latest source build of UAssetGUI This is the error I come across:

"Failed to parse this file! System.FormatException: Asset has AdditionalPackagesToCook and is likely too old to be parsed"

The umap in question: https://drive.google.com/drive/folders/1Y2fMswl0IXaObm79rUhbTslm8U-_iWB8?usp=sharing