The OpenAPI service might result in a high CPU usage without doing any operation. The issue seems to occur more after an update on VM environments when the license might be broken due to a change in the activation key. The continuous check of the activation key generates the high CPU usage.
Check the logs for license error, if you find license errors, mainly about a different activation key, please update the license via the UI control panel. After the license is updated the activation key errors will be cleared and the service will return to regular functions.