PS> '}' | Group-Object

Count  Name    Group
-----  ----    -----
    1  }       {}}

PS> '}' | Group-Object
Group-Object: Input string was not in a correct format. Failure to parse near offset 1. Unexpected closing brace without a corresponding opening brace.

Exception             :
    Type       : System.FormatException
    TargetSite :
        Name          : ThrowFormatInvalidString
        DeclaringType : System.ThrowHelper, System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e
        MemberType    : Method
        Module        : System.Private.CoreLib.dll
    Message    : Input string was not in a correct format. Failure to parse near offset 1. Unexpected closing brace without a corresponding opening brace.
    Source     : System.Private.CoreLib
    HResult    : -2146233033
    StackTrace :
   at System.Text.StringBuilder.AppendFormatHelper(IFormatProvider provider, String format, ReadOnlySpan`1 args)
   at Microsoft.PowerShell.Commands.GroupInfo.BuildName(List`1 propValues)
   at Microsoft.PowerShell.Commands.GroupObjectCommand.DoOrderedGrouping(OrderByPropertyEntry currentObjectEntry, Boolean noElement, List`1 groups, Dictionary`2 groupInfoDictionary, OrderByPropertyComparer
orderByPropertyComparer)
   at Microsoft.PowerShell.Commands.GroupObjectCommand.EndProcessing()
   at System.Management.Automation.CommandProcessorBase.Complete()
CategoryInfo          : NotSpecified: (:) [Group-Object], FormatException
FullyQualifiedErrorId : System.FormatException,Microsoft.PowerShell.Commands.GroupObjectCommand
InvocationInfo        :
    MyCommand        : Group-Object
    ScriptLineNumber : 1
    OffsetInLine     : 7
    HistoryId        : 54
    Line             : '}' | Group-Object
    Statement        : Group-Object
    PositionMessage  : At line:1 char:7
                       + '}' | Group-Object
                       +       ~~~~~~~~~~~~
    InvocationName   : Group-Object
    CommandOrigin    : Internal
ScriptStackTrace      : at <ScriptBlock>, <No file>: line 1