Credit/Debit Card Tip Missing?

It happened again yesterday. Probably the third time in the last few months.

Had lunch and put the tab on my debit card and included a tip. When I viewed my account on-line this morning I happened to notice that my account only reflected the base bill sans tip.
Any idea why this happens?
Since I don't get to this place often, should I call the restaurant and see if somehow I can correct this...assuming it is not some sort of processing flow?
What would you do?
Thanks

When the server swipes your card your account gets "authorized" for an amount. In a restaurant this would be the sale amount before tip. At the end of the night each server takes the signed receipts to the register and adjusts the sale to add the tip amount. Then the whole nights batch of transactions gets settled or deposited. After settlement has occurred it is impossible to go back and adjust a transaction for a tip. So if the server forgets to adjust their tips, they lose that tip. However, you will not see the adjusted amount on your online banking for several days, you will only see the authorized amount. After the transactions are processed by all the banks involved the transaction will move from pending to posted for the full amount plus tip. Something very similar happens when you buy gas at the pump with your credit card. The pump authorizes your account for $1.00 but it settles the transaction for the full amount of your gas purchase.

That happens on my card but the tip usually shows up in the total a few days later. Check your account in about 3 days and see if the total shows correctly with the tip. Not sure as to the reason.

Ahh, grasshopper now understands.
Thanks.

Another possibility is that the server lost the cc slip or you accidentally put it in your wallet. The base amount will have been swiped into the machine, but with a lost slip the tip cannot be added. In the past I've had servers come to me to say that while they can't find the cc slip from table 1, they remember seeing a $10 tip on it. True or not - no slip, no tip.

Believe it or not, some places often forget to send the credit card machine batch after that day's end of business. I've noticed that the credit/debit card transactions of some of the establishments I frequent don't often post for three or four days.