Based on the provided information, the current installed version of Telerik Reporting assemblies is 188.8.131.52.
I confirm that there is a problem with DocumentFormat.OpenXml.dll version 2.7.2+ that slipped in this release. The issue is fixed in internal build 184.108.40.206.
A possible workaround with this version is described in Telerik Reporting R1 2019 fails to load assembly DocumentFormat.OpenXml 2.7.2+
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