Fix random crash after hot reload

Reproduction steps unclear.

While following the JSF customization test scenarios, a hot reload was performed after Table Layout & Content View test scenario:

In Configuration > Listings & Views > Table Layouts:
Create a custom table layout, with:

title with link,
description,
dc:subjects.
Configuration > Listings & Views > Content Views
Create a content view using Elasticsearch index and based on:

ecm:mixinType != 'HiddenInNavigation' AND ecm:isCheckedInVersion = 0 AND ecm:currentLifeCycleState != 'deleted' AND ecm:primaryType = 'File'
In Query & Form on the Search Layout part:

Add dc:title, dc:creator and dc:created.
Use relevant widgets for configuration.
In Results on the Result columns part: 
Check “Reference an existing table layout”.
Choose previously created table layout.
In Query & Form on Default sort set an order(ex:dublincore) based in the description field.
In Results on the Advanced Configuration part uncheck Show CSV export and Show page size selector.
Still in Results set Number of results per page to “2”.
Uncheck Enable common actions (copy, paste, delete...).
In Query & Form on the Flags part set the Search content View flag.

Hot-reload.

The server crashed immediately after the hot reload. The JSF error page appeared, but clicking on the "back to home page" button caused further errors. I had to restart the server (2018-11-29T15:55:27,721) and afterwards I couldn't reproduce the problem.

Server logs attached. The hot reload in question begin on line 3232 (2018-11-29T15:39:52,386)