In December I reported a Google Maps Coupon Bug where if you entered an expiration date the coupon would never show up. It appears that the bug still exists although in slightly less virulent form. There have been a number of reports in the Google Maps For Business Groups where if you select an expiration date the coupon defaults back to no expiration and no date appears on the coupon:

TOPIC: coupons not allowing expiration date

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== 1 of 1 ==
Date: Tues, Feb 12 2008 7:01 am
From: bullwinkle

Hmm…Jen I think you’re not understanding. Nobody is doing anything
wrong. Clicking on the radio button and selecting a future date from
the calendar then clicking on continue, results in being returned to
the local tab instead of coupons, then clicking on the coupon tab
reveals that the coupon is now activated but there is NO expiration
date, it says “Never Expires”. Going back into edit, shows that the
“Never expires” radio button is once again selected. We cannot set a
date and have it “stick”. It’s that simple. It’s not rocket science,
it’s just plain broken. I’ve tried it repeatedly with both Firefox
and ie7 and neither works. It appears that the only thing we users
can do, is to not use google coupons!

For now the only solution to having an expiration date is to manage the process manually. When you create a coupon, enter the expiration date manually on the coupon body and then be sure to remove the coupon at the end of your promotion