What is running, and where it is not
Google is testing a "Deal Ends" annotation on Product Listing Ads: a real-time badge such as "3 days left" attached to the Shopping ad. Search Engine Roundtable reports the test is global, excluding the EEA, Switzerland and the UK.
The input has not been described. Merchant Center already carries promotion start and end dates, and a countdown is the natural consumer of that field, but Google has not said the badge draws from it. Until that is confirmed, the useful posture is knowing which of your dates would be exposed if it does.
The exclusions carry information of their own. The EEA, Switzerland and the UK apply the tightest rules on countdown claims and reference pricing of any market in the test's footprint, and leaving all three out at once points at promotional-claims risk rather than a rendering problem.
What to do about it
Audit promotion end dates for ones that already passed
A promotion end date that is wrong today is a tidiness issue nobody sees. If a countdown starts rendering from it, the same field becomes a claim on a paid ad, and a badge counting down to a date that already went by is worse than no badge. Sweep the feed for promotions whose end dates are stale or were set as placeholders, and fix those regardless of whether this test ever reaches your account.