The issue is because of migration. If a customer has migrated from any lower version to MDM 912 and tried to add the child records from BW then the child record will not get added, because of PRINCIPALKEY INDEX and fields "[CREATIONDATE] [datetime2](0) NOT NULL,[MODDATE] [datetime2](0) NOT NULL".

Resultant, the patterns search not able to find an associated child for a particular parent, but in actual, the record was nit added by BW because of the migration issue.

Here is the PRINCIPALKEY Table STRUCTURE:
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CREATE TABLE [dbo].[PRINCIPALKEY](
[CATALOGID] [numeric](22, 0) NOT NULL,
[PRODUCTKEYID] [numeric](22, 0) NOT NULL,
[MODVERSION] [numeric](22, 0) NOT NULL,
[CATALOGVERSIONNUMBER] [numeric](22, 0) NOT NULL,
[ACTIVE] [nvarchar](1) NOT NULL,
[CREATIONDATE] [datetime2](0) NOT NULL,
[MODDATE] [datetime2](0) NOT NULL,
[MODMEMBERID] [numeric](22, 0) NOT NULL,
[LASTIMPORTTIME] [numeric](31, 8) NOT NULL,
[CHECKSUM] [numeric](31, 8) NOT NULL,
[STATE] [nvarchar](255) NOT NULL,
[PARENTVERSION] [numeric](22, 0) NOT NULL,
[OWNERID] [numeric](22, 0) NULL,
[OWNERTYPE] [numeric](22, 0) NULL,
[LASTCONFIRMEDVERSION] [numeric](22, 0) NULL,
[PROCESSLOGID] [numeric](22, 0) NULL,
[BATCHID] [numeric](22, 0) NULL,
[EFFECTIVEDATE] [datetime2](3) NULL,
[ENDEFFECTIVEDATE] [datetime2](3) NULL,
 CONSTRAINT [XPK_PRINCIPALKEY] PRIMARY KEY CLUSTERED
(
[CATALOGID] ASC,
[PRODUCTKEYID] ASC,
[MODVERSION] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
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This will not happen for every record, this will happen only in the case where there is a timestamps rounding happens.