There is no such option for just notification. You have to overwrite thresholds for services to not alert to early, but in general Dynatrace is learning baselines. If you have applications that have 20% failure rate and it is normal (sometimes it is) after few days DT should stop making problems because it will learn such behaviour.
@jose r. As of right now there is now way to configure that at the problem alert level. You can adjust the time that a ticket gets generated, for example - Alert once a problem is open for 10 mins. You can adjust your failure rate thresholds as well as create static alerting too and define the failure rate percentage within the settings page. Keep in mind, you can do this at a single process/service/transaction level, or you can do this globally.
This can be done by going to the process/service/transaction, selecting "Edit" and selecting "Anomaly detection" and Set failure rate to a custom threshold.
Note in the last image Global detection settings is disabled, so this single transaction level will not include any global permissions as you are defining and over ridding the global setting.
Global Level (the entire environment, excluding anything that does not have the global anomaly detection applied from the image above):
Go into settings from the bottom left side of the page and select "Anomaly Detection" and pick the applicable technology level you want to adjust the failure rate for. Then change it from "Automatically" to "Using fixed thresholds" and define it as desired.
As stated previously, Everything that is set to run off the global permission will now be subject to the defined failure rate that is set via the global setting.
Let me know if you have any questions!