Getting literal ampersands from summary field in a view of fields
Override the template and use the twig filter "raw":


Add template file to your custom theme. E.g. /themes/custom/MYTHEME/templates/views-view-field.html.twig
In the above template file add {{ output|raw }} 
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  The raw filter marks the value as being "safe", which means that in an
  environment with automatic escaping enabled this variable will not be
  escaped


Source: https://twig.symfony.com/doc/2.x/filters/raw.html