Trying to enable the in-memory caching for the first time results in a wicket error

Description

org.apache.wicket.WicketRuntimeException: The component(s) below failed to render. Possible reasons could be that:
	1) you have added a component in code but forgot to reference it in the markup (thus the component will never be rendered),
	2) if your components were added in a parent container then make sure the markup for the child container includes them in <wicket:extend>.

1. [Component id = title, page = org.geoserver.gwc.web.GWCSettingsPage, path = form:cachingOptionsPanel:container:configs:blobstores:container:statsContainer:title, type = org.apache.wicket.markup.html.basic.Label, isVisible = true, isVersioned = true]

	at org.apache.wicket.Page.checkRendering(Page.java:666)
	at org.apache.wicket.Page.onAfterRender(Page.java:821)
	at org.apache.wicket.markup.html.WebPage.onAfterRender(WebPage.java:224)
	at org.apache.wicket.Component.afterRender(Component.java:919)
	at org.apache.wicket.Component.render(Component.java:2341)
	at org.apache.wicket.Page.renderPage(Page.java:1018)

Indeed the "title" label is added, completely empty, but there is no equivalent component in the HTML. Not sure why it does not always happen.