Reports do not evaluate custom URL field

For Projects I created a custom field type URL “ExternalLink” which constructs a URL from another custom field “ExternalRef”.
The ExternalLink constructs the link just fine in Detail view, however when running a Report that includes that, the custom URL appears as a clickable link but instead of the value of "ExternalRef " being included as the distinct value in each project, the link appears as follows:


instead of (for example where the value of ExternalRef =pipeline)


When I click on the link it takes me to that, incorrect “Array”, address.
What should I do to have the Report perform the substitution before presenting the link?
Thanks and regards,