Might be related to Chart not working - Exception.
I just tried the latest snapshot and all looks good:
ID │ Servlet │ Servlet-Name │ State │ Alias │ Url
────┼────────────────────────┼─────────────────┼─────────────┼───────────────┼──────────────────
214 │ HueEmulationServlet │ ServletModel-41 │ Deployed │ /api │ [/api/*]
139 │ AsyncProxyServlet │ ServletModel-21 │ Deployed │ /proxy │ [/proxy/*]
207 │ ResourceServlet │ /basicui:web │ Deployed │ /basicui │ [/basicui/*]
172 │ DashboardServlet │ ServletModel-11 │ Deployed │ /start/index │ [/start/index/*]
172 │ ResourceServlet │ /start:web │ Deployed │ /start │ [/start/*]
216 │ RRD4jChartServlet │ ServletModel-44 │ Deployed │ /rrdchart.png │ [/rrdchart.png/*]
140 │ IconServlet │ ServletModel-23 │ Deployed │ /icon │ [/icon/*]
168 │ IconForwarder │ ServletModel-47 │ Deployed │ /images │ [/images/*]
95 │ AudioServlet │ ServletModel-15 │ Undeployed │ /audio │ [/audio/*]
207 │ CmdServlet │ ServletModel-26 │ Deployed │ /basicui/CMD │ [/basicui/CMD/*]
209 │ AsyncServlet │ ServletModel-38 │ Deployed │ /upnpcallback │ [/upnpcallback/*]
95 │ AudioServlet │ ServletModel-17 │ Deployed │ /audio │ [/audio/*]
207 │ WebAppServlet │ ServletModel-29 │ Deployed │ /basicui/app │ [/basicui/app/*]
139 │ ChartServlet │ ServletModel-19 │ Deployed │ /chart │ [/chart/*]
218 │ ResourceServlet │ /habpanel:web │ Deployed │ /habpanel │ [/habpanel/*]
215 │ ResourceServlet │ /doc:swagger │ Deployed │ /doc │ [/doc/*]
15 │ ServletContainerBridge │ ServletModel-5 │ Deployed │ /rest │ [/rest/*]
208 │ ResourceServlet │ /paperui:web │ Deployed │ /paperui │ [/paperui/*]
… while I see that there is a similar issue with the AudioServlet…
Does this happen right after startup? Could you post some logs around the NamespaceException?