I had the same issue after upgrading to 150.1427.0 version of nuget package. It appears when I pass int or datetime values as parameters
Exception: System.NullReferenceException: Object reference not set to an instance of an object.
at Microsoft.ReportingServices.Common.DateTimeUtil.ParseDateToDefaultFormat(String strDateTime, CultureInfo formatProvider)
at Microsoft.Reporting.WebForms.ServerReport.SetParameters(IEnumerable`1 parameters)
According to the release notes they "Fixed a datetime parsing issue affecting certain locales."
https://docs.microsoft.com/en-us/sql/reporting-services/application-integration/release-notes-ssrs-application-integration?view=sql-server-ver15
So I downgraded to version 150.1404.0 and the issue has gone
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