To reproduce:
- Create a shape with QGIS and add it to RadMap using the approach described in the documentation: http://docs.telerik.com/devtools/winforms/map/file-readers/esri-shapefile-reader

How to reproduce: Check the attached project and video

Workaround: force an update in the MapElement
Public Class RadForm1

    Private bingKey As String = ""
    Dim myTimer As Timer
    Public Sub New()

        InitializeComponent()
        Dim bingProvider As BingRestMapProvider = New Telerik.WinControls.UI.BingRestMapProvider()
        bingProvider.UseSession = True
        bingProvider.BingKey = bingKey

        AddHandler bingProvider.SearchCompleted, AddressOf bingProvider_SearchCompleted

        Me.RadMap1.Providers.Add(bingProvider)

        myTimer = New Timer
        myTimer.Interval = 500
        AddHandler myTimer.Tick, AddressOf OnMyyTimerTick
    End Sub

    Private Function OnMyyTimerTick() As Object
        myTimer.Stop()
        Me.RadMap1.MapElement.InvalidateMeasure(True)
    End Function

    Private Sub bingProvider_SearchCompleted(sender As Object, e As SearchCompletedEventArgs)

        myTimer.Start()

    End Sub
End Class

Error:

System.ArgumentException was unhandled
  HResult=-2147024809
  Message=An item with the same key has already been added.
  Source=mscorlib
  StackTrace:
       at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
       at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
       at Telerik.WinControls.UI.DbfHeader.CreateExtendedPropertySet()
       at Telerik.WinControls.UI.DbfReader..ctor(Stream stream, ExtendedPropertySet propertySet, Encoding encoding)
       at Telerik.WinControls.UI.ShapeFileReader.Read(ShapeFileReaderParameters parameters)
       at _1125357MapShapeFiles.RadForm1..ctor() in d:\Projects\1125357MapShapeFiles\RadForm1.cs:line 37
       at _1125357MapShapeFiles.Program.Main() in d:\Projects\1125357MapShapeFiles\Program.cs:line 17
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

There is a noticeable delay after moving the mouse while panning the map. After making a comparison with Open Street Maps and a local provider, it seems that the local provider is slightly slower than the OSM provider. Please refer to the attached gif file. 

After profiling the project, it seems that Image.FromFile for loading the required tile takes most of the time:

With the OSM the tile is loaded by using Image.FromStream and it takes 3 times less time:

Please refer to the attached gif file. The sample project together with the sample files of the local provider can be downloaded here: https://1drv.ms/u/s!AnnV2HsINMD_yxDEY2iOWHXn5V9_?e=VurA0N