Downgraded to 18.4.0.30 and the issue is fixed. Now I get another error.
Exception thrown: 'System.Windows.Markup.XamlParseException' in PresentationFramework.dll
Initialization of 'Syncfusion.Windows.Tools.Controls.DropDownButton' threw an exception.
The thread 0x847c has exited with code 0 (0x0).
The thread 0x8878 has exited with code 0 (0x0).
System.Xaml.XamlObjectWriterException: Set property 'System.Windows.ResourceDictionary.Source' threw an exception. ---> System.IO.IOException: Cannot locate resource 'controls/sfbadge/themes/generic.xaml'.
at MS.Internal.AppModel.ResourcePart.GetStreamCore(FileMode mode, FileAccess access)
at System.IO.Packaging.PackagePart.GetStream(FileMode mode, FileAccess access)
at System.IO.Packaging.PackWebResponse.CachedResponse.GetResponseStream()
at System.IO.Packaging.PackWebResponse.get_ContentType()
at MS.Internal.WpfWebRequestHelper.GetContentType(WebResponse response)
at System.Windows.ResourceDictionary.set_Source(Uri value)
at MS.Internal.Xaml.Runtime.ClrObjectRuntime.SetValue(Object inst, XamlMember property, Object value)
--- End of inner exception stack trace ---
at MS.Internal.Xaml.Runtime.ClrObjectRuntime.SetValue(Object inst, XamlMember property, Object value)
at MS.Internal.Xaml.Runtime.PartialTrustTolerantRuntime.SetValue(Object obj, XamlMember property, Object value)
at System.Xaml.XamlObjectWriter.Logic_ApplyPropertyValue(ObjectWriterContext ctx, XamlMember prop, Object value, Boolean onParent)
at System.Xaml.XamlObjectWriter.Logic_DoAssignmentToParentProperty(ObjectWriterContext ctx)
at System.Xaml.XamlObjectWriter.Logic_AssignProvidedValue(ObjectWriterContext ctx)
at System.Xaml.XamlObjectWriter.WriteEndMember()
at System.Xaml.XamlServices.Transform(XamlReader xamlReader, XamlWriter xamlWriter, Boolean closeWriter)
at System.Windows.SystemResources.ResourceDictionaries.LoadDictionary(Assembly assembly, String assemblyName, String resourceName, Boolean isTraceEnabled, Uri& dictionarySourceUri)
at System.Windows.SystemResources.ResourceDictionaries.LoadGenericDictionary(Boolean isTraceEnabled)
at System.Windows.SystemResources.FindDictionaryResource(Object key, Type typeKey, ResourceKey resourceKey, Boolean isTraceEnabled, Boolean allowDeferredResourceReference, Boolean mustReturnDeferredResourceReference, Boolean& canCache)
at System.Windows.SystemResources.FindResourceInternal(Object key, Boolean allowDeferredResourceReference, Boolean mustReturnDeferredResourceReference)
at System.Windows.StyleHelper.GetThemeStyle(FrameworkElement fe, FrameworkContentElement fce)
at System.Windows.FrameworkElement.UpdateThemeStyleProperty()
at System.Windows.FrameworkElement.OnInitialized(EventArgs e)
at System.Windows.FrameworkElement.TryFireInitialized()
at System.Windows.Controls.ItemsControl.EndInit()
at MS.Internal.Xaml.Runtime.ClrObjectRuntime.InitializationGuard(XamlType xamlType, Object obj, Boolean begin)