The following error is appearing in the event logs of one or more servers in the Farm:
Load control template file /_controltemplates/15/NWLOnlineComponents.ascx failed: The expression prefix 'NWLResources' was not recognized. Please correct the prefix or register the prefix in the section of configuration.
To remove the error you can update your web.config file by adding the following text to the section (please backup the web.config file first!)
<add expressionPrefix="NWLResources" type="Nintex.Workflow.Live.Localization.NWLResourceExpressionBuilder, Nintex.Workflow.Live, Version=220.127.116.11, Culture=neutral, PublicKeyToken=bd539bd4aa1e2820" />