[sql] SQL Server 2012 column identity increment jumping from 6 to 1000+ on 7th entry

I have a strange scenario in which the auto identity int column in my SQL Server 2012 database is not incrementing properly.

Say I have a table which uses an int auto identity as a primary key it is sporadically skipping increments, for example:

1, 2, 3, 4, 5, 1004, 1005

This is happening on a random number of tables at very random times, can not replicate it to find any trends.

How is this happening? Is there a way to make it stop?

While trace flag 272 may work for many, it definitely won't work for hosted Sql Server Express installations. So, I created an identity table, and use this through an INSTEAD OF trigger. I'm hoping this helps someone else, and/or gives others an opportunity to improve my solution. The last line allows returning the last identity column added. Since I typically use this to add a single row, this works to return the identity of a single inserted row.

The identity table:

CREATE TABLE [dbo].[tblsysIdentities](
[intTableId] [int] NOT NULL,
[intIdentityLast] [int] NOT NULL,
[strTable] [varchar](100) NOT NULL,
[tsConcurrency] [timestamp] NULL,
CONSTRAINT [PK_tblsysIdentities] PRIMARY KEY CLUSTERED 
(
    [intTableId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF,  ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

and the insert trigger:

-- INSERT --
IF OBJECT_ID ('dbo.trgtblsysTrackerMessagesIdentity', 'TR') IS NOT NULL
   DROP TRIGGER dbo.trgtblsysTrackerMessagesIdentity;
GO
CREATE TRIGGER trgtblsysTrackerMessagesIdentity
ON dbo.tblsysTrackerMessages
INSTEAD OF INSERT AS 
BEGIN
    DECLARE @intTrackerMessageId INT
    DECLARE @intRowCount INT

    SET @intRowCount = (SELECT COUNT(*) FROM INSERTED)

    SET @intTrackerMessageId = (SELECT intIdentityLast FROM tblsysIdentities WHERE intTableId=1)
    UPDATE tblsysIdentities SET intIdentityLast = @intTrackerMessageId + @intRowCount WHERE intTableId=1

    INSERT INTO tblsysTrackerMessages( 
    [intTrackerMessageId],
    [intTrackerId],
    [strMessage],
    [intTrackerMessageTypeId],
    [datCreated],
    [strCreatedBy])
    SELECT @intTrackerMessageId + ROW_NUMBER() OVER (ORDER BY [datCreated]) AS [intTrackerMessageId], 
    [intTrackerId],
   [strMessage],
   [intTrackerMessageTypeId],
   [datCreated],
   [strCreatedBy] FROM INSERTED;

   SELECT TOP 1 @intTrackerMessageId + @intRowCount FROM INSERTED;
END

Got the same problem, found the following bug report in SQL Server 2012 If still relevant see conditions that cause the issue - there are some workarounds there as well (didn't try though). Failover or Restart Results in Reseed of Identity