Restart after Error "Fatal transport error: Too many open files"

Hi to all.
After updating to Milestone M5 from stable 2.3 first i recognised that the cpu load increases from 2% up to 6% in the middle. And every 6-8 hours up to 20 % for a short time. I can see it in the chart.
After searching in the log and events.files i found this:

2018-11-04 02:08:31.716 [ERROR] [    ] - Fatal transport error: Too many open files
2018-11-04 02:08:31.717 [ERROR] [ab.binding.http.internal.HttpBinding] - No response received from '***/s$2Fmp/sensors/11'
2018-11-04 02:08:32.224 [hingStatusInfoChangedEvent] - 'hue:bridge:0017****' changed from ONLINE to OFFLINE: Verbindung zur Hue Bridge unterbrochen.

The system restarts after the Error.
Before updating to M5 all runs okay. Can anyone give me a hint?
Thanks for help and greetings,

Sorry for creating a new topic. Think here should be the problem.