Performance Insights Shows Nothing After Changing Instance Type from db.r5.8xlarge to db.r5.16xlarge for Aurora MySQL

We were originally using a db.r5.8xlarge as our write instance, and Performance Insights was displaying the DB load queries properly. However, after updating to a db.r5.16xlarge more than a week ago, nothing has been displayed in the DB load on Performance Insights. Given that we often experience heavy load situations with CPU usage over 80%, it seems unlikely that the absence of recorded data is due to a lack of DB load. The performance_schema, which many guides suggest checking, is currently set to System default, so it doesn't seem to be the issue either.

The measures we have taken include:

1. Resetting the performance_schema and then rebooting the DB instance.
2. Turning off Performance Insights and rebooting, and waiting for 2 hours before turning it back on and rebooting. (After this, one query was saved in the DB load, but then it stopped saving again.) An interesting fact is that the read replicas added within the same Aurora cluster are also not accumulating any DB load in Performance Insights despite being enabled.

Is there anything we need to check more?