Telerik.Reporting.OpenXmlRendering.2.7.2.dll from the latest release (R1 2009) references the from version of DocumentFormat.OpenXml. See the screenshot:
Here the screenshot for the prev version (R3 2018 SP2):
Because of this our projects referencing DocumentFormat.OpenXml 2.8.1 (the latest version) are all broken. Xlsx rendering simply does not work anymore.