Issue on a simple model with Nov 2020 release of PBI Desktop.

[DamuVenkatesan]

I received this error while I am testing a simple relationship.   I did not get any error but got a frown.  Please let me know after your research.

Feedback Type:
Frown (Error)

Timestamp:
2020-12-13T03:17:20.1456036Z

Local Time:
2020-12-12T22:17:20.1456036-05:00

Session ID:
82a202fd-81e0-400d-a74e-da8fd494f981

Release:
November 2020

Product Version:
2.87.762.0 (20.11) (x64)

Stack Trace:
at Microsoft.PowerBI.Client.Windows.AnalysisServices.Relationships.DataModel.<>c__DisplayClass13_0.<Refresh>b__1(IRelationship r)
at System.Linq.Enumerable.WhereListIterator`1.MoveNext()
at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
at Microsoft.PowerBI.Client.Windows.AnalysisServices.Relationships.DataModel.Refresh(IEnumerable`1 modelingTables, IEnumerable`1 modelingRelationships)
at Microsoft.PowerBI.Client.Windows.AnalysisServices.Relationships.RelationshipManager.RollbackChanges()
at Microsoft.PowerBI.Client.Windows.FloatingDialog.KoEditRelationshipDialog.<OnWindowClosing>b__50_0()
at Microsoft.Mashup.Host.Document.ExceptionHandlerExtensions.HandleExceptions(IExceptionHandler exceptionHandler, Action action)

PowerBINonFatalError:
{"AppName":"PBIDesktop","AppVersion":"2.87.762.0","ModuleName":"Microsoft.PowerBI.Client.Windows.dll","Component":"Microsoft.PowerBI.Client.Windows.AnalysisServices.Relationships.DataModel+<>c__DisplayClass13_0","Error":"System.NullReferenceException","MethodDef":"<Refresh>b__1","ErrorOffset":"161"}

OS Version:
Microsoft Windows NT 10.0.19041.0 (x64 en-US)

CLR Version:
4.7 or later [Release Number = 528372]

Peak Virtual Memory:
38.6 GB

Private Memory:
907 MB

Peak Working Set:
1.07 GB

IE Version:
11.630.19041.0

User ID:
476d1fc6-da31-4adb-b3d6-48a0dbc30d52

Workbook Package Info:
1* - en-US, Query Groups: 0, fastCombine: Disabled, runBackgroundAnalysis: True.

Telemetry Enabled:
True

Model Default Mode:
Import

Model Version:
PowerBI_V3

Is Report V3 Models Enabled:
True

Enabled Preview Features:
PBI_NewWebTableInference
PBI_v3ModelsPreview

Disabled Preview Features:
PBI_shapeMapVisualEnabled
PBI_SpanishLinguisticsEnabled
PBI_JsonTableInference
PBI_ImportTextByExample
PBI_ExcelTableInference
PBI_qnaLiveConnect
PBI_azureMapVisual
PBI_dataPointLassoSelect
PBI_narrativeTextBox
PBI_dynamicParameters
PBI_anomalyDetection
PBI_newFieldList

Disabled DirectQuery Options:
TreatHanaAsRelationalSource

Cloud:
GlobalCloud

DPI Scale:
125%

Supported Services:
Power BI

Thank you,
Damu Venkatesan

[v-chuncz-msft]

@DamuVenkatesan 

I tried the latest version (2.87.1061.0) and it works fine for me. You may try to recreate the report.