A layer's configuration is saved differently if it is saved by the "Layers" page or by the "Tile Layers" page.
From "Tile Layers" layers list, click on a layer name, move to the "Data" tab, Save
Go to the "Layers" page, get the wicket exception
Note: the layer must appear in the list to trigger the bug, so you might need to search for it to experience the bug.
Here is the stacktrace:
The difference in the featuretype.xml configuration files is the "crs" definition inside the "latLonBoundingBox".
The original layer configuration had the following:
While the configuration that triggers the bug is: