System.ArgumentOutOfRangeException - SMSG_UPDATE_OBJECT (3.4.2.50063)

System.ArgumentOutOfRangeException
Index and length must refer to a location within the string. (Parameter 'length')
   at System.String.ThrowSubstringArgumentOutOfRange(Int32 startIndex, Int32 length)
   at System.String.Substring(Int32 startIndex, Int32 length)
   at WowPacketParser.Misc.Packet.FormatFloat(Single value) in C:\Users\benjy\Documents\GitHub\WowPacketParser\WowPacketParser\Misc\PacketReads.cs:line 742
   at WowPacketParser.Misc.Packet.ReadSingle(String name, Object[] indexes) in C:\Users\benjy\Documents\GitHub\WowPacketParser\WowPacketParser\Misc\PacketReads.cs:line 362
   at WowPacketParserModule.V2_5_1_38707.Parsers.UpdateHandler.ReadMovementUpdateBlock(Packet packet, WowGuid guid, WoWObject obj, Object index) in C:\Users\benjy\Documents\GitHub\WowPacketParser\WowPacketParserModule.V2_5_1_38707\Parsers\UpdateHandler.cs:line 436
   at WowPacketParserModule.V2_5_1_38707.Parsers.UpdateHandler.ReadCreateObjectBlock(Packet packet, CreateObject createObject, WowGuid guid, UInt32 map, CreateObjectType createType, Object index) in C:\Users\benjy\Documents\GitHub\WowPacketParser\WowPacketParserModule.V2_5_1_38707\Parsers\UpdateHandler.cs:line 175
   at WowPacketParserModule.V2_5_1_38707.Parsers.UpdateHandler.HandleUpdateObject(Packet packet) in C:\Users\benjy\Documents\GitHub\WowPacketParser\WowPacketParserModule.V2_5_1_38707\Parsers\UpdateHandler.cs:line 150
   at WowPacketParser.Parsing.Handler.Parse(Packet packet, Boolean isMultiple) in C:\Users\benjy\Documents\GitHub\WowPacketParser\WowPacketParser\Parsing\Handler.cs:line 149

Start with WowPacketParser/Misc/PacketReads.cs at FormatFloat, then trace the ReadSingle call from WowPacketParserModule.V2_5_1_38707/Parsers/UpdateHandler.cs in ReadMovementUpdateBlock. Reproduce the SMSG_UPDATE_OBJECT failure for client version 3.4.2.50063 and determine how the reported substring bounds should be handled; done means the packet parses without this exception.