In this scenario, the reported behavior is observed in NET 8. The same behavior is not reproducible in .Net Framework 4.8. When the map is zoomed max out and we try to pan the view, missing tiles appear and the performance is very slow. Additionally, in the output tab of VS, we can observe some exceptions:

In this case, we have 2 providers. The first one is regular OpenStreetMap and the second one with a different ImageURL address is rendered on top. The tile images downloaded from the second provider are transparent. However, this transparency is not respected from the control and the transparent areas are drawn with black color. 

In this case, we have missing image tiles while zooming and scrolling the map. When downloading a tile, the internal WebClient is returning an error with the following message: The server committed a protocol violation. Section=ResponseStatusLine. The WebException does not have a Response. This scenario is not handled in code which will lead to missing image tiles. Zooming the same area will reload the missing tiles, but still, it should be handled in the source code.

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

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 

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:

Add a MapPath object to a layer of RadMap and zoom in to the last possible level. 
An exception is thrown.

Is there a way to not allow the map to WrapAround? 

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: