The Flink semantics of a counter are not matching with the counters in DataDog.
In Flink a counter counts the total of increment and decrement calls.
In DataDog a counter is a rate over the reporting interval.
The Flink implementation of the DataDog reporter seems to send the Flink counter value each time the metrics are reported. Correct would be to send the delta of the counter since the last report.
There are some features in DataDog which are easier to use if this could be fixed, e.g. alerts based on counters.