A SQL Server technology that supports the creation, management, and delivery of both traditional, paper-oriented reports and interactive, web-based reports.
Hi @Dom
From what I've searched, this seems to be an issue with caching, try deleting the ".data" file created in the same directory as the report.
For more details, you can refer to this link: https://social.msdn.microsoft.com/Forums/sqlserver/en-US/fad557d1-f32b-4291-a5ef-33220a99fa1b/the-value-expression-used-in-textrun-8216textboxparagraphs0textruns08217-returned-a-data?forum=sqlreportingservices.
If the answer is helpful, please click Accept Answer and Up-Vote for the same. If you have any questions, please feel free to let me know.
Best regards,
Aniya