The charts on the Metrics panel of the Redis Enterprise dashboard are averages. For example, the CPU is checked once every 20 sec. We check the CPU usage over the last 1 sec and compare it to the thresholds, therefore a single spike during the previous 19 sec won't be noticed and no email alert is sent. This is the main reason you cannot see the CPU spikes on the Weekly (or higher) scale. Check the Minute or 5 Minutes to be able to see them, but keep in mind that these are averages and depend on how long the CPU usage reached the high value and when the sample was taken.

References

Refer to resource usage metrics.