"gc buffer busy acquire" wait event and the Cluster wait class

I have an 18c RAC db recently hit with high "gc buffer busy acquire" wait events. I've been researching that wait, and have digested WAITEVENT: "gc buffer busy acquire/release " Reference Note (Doc ID 2256780.1). Info in the doc has helped and we are on our way to addressing the issue. Still, a question. In the doc there is this section:

In 11.1 and earlier version, this type of waits are grouped as “gc buffer busy” waits.

starting with Oracle database 11g Release 2, the “gc buffer busy” waits are categorized into two new wait categories:

• gc buffer busy acquire

• gc buffer busy release