Splitpoints doesn't work with imported cuesheet

[NeoCoderMatrix86]

Describe the bug
Splitting audio file doesn't work, when the audio file was imported from cuesheet.

Exception details (if possible)
blazor.webassembly.js:1 crit: Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer[100]
Unhandled exception rendering component: ContentStream wasn't loaded!
System.Exception: ContentStream wasn't loaded!
at AudioCuesheetEditor.Model.IO.Audio.AudioConverterService.SplitAudiofileAsync(Audiofile audiofile, TimeSpan from, Nullable1 to) in C:\tmp\AudioCuesheetEditor\AudioCuesheetEditor\Model\IO\Audio\AudioConverterService.cs:line 74 at AudioCuesheetEditor.Model.IO.Export.ExportfileGenerator.GetAudiofileContentAsync(String audiofileName, Nullable1 from, SplitPoint splitPoint) in C:\tmp\AudioCuesheetEditor\AudioCuesheetEditor\Model\IO\Export\ExportfileGenerator.cs:line 379
at AudioCuesheetEditor.Model.IO.Export.ExportfileGenerator.GenerateExportfilesAsync(ExportType exportType) in C:\tmp\AudioCuesheetEditor\AudioCuesheetEditor\Model\IO\Export\ExportfileGenerator.cs:line 118
at AudioCuesheetEditor.Shared.ModalExportdialog.GenerateExportfiles_Clicked() in C:\tmp\AudioCuesheetEditor\AudioCuesheetEditor\Shared\ModalExportdialog.razor:line 247
at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
at Blazorise.Button.ClickHandler(MouseEventArgs eventArgs)
at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)

To Reproduce
Steps to reproduce the behavior:

1. Import the sample cuesheet
2. Add a splitpoint
3. Export cuesheets
4. See error