Is TicketID an identity field?

What kind of data is in ActDtim?

Since the clustered key is the three columns combined, and if you have datetime as the data type in ActDtim, then it is perceivable that the lowest identity is not listed as the first record in the clustered index. A misaligned insert statement could have inserted into your table with an invalid date that predated the lowest identity value you have in the table and produce the irregular results.