Unicorn processes use 100 percent of CPU since upgrading to 12.4.0 CE

Since upgrading to 12.4.0 this morning, we see that displaying the Changes Tab under Merge Requests is very slow. It takes up to 1.5 minutes to display the Diff in certain repos. This does not seem to affect all repos. We see that the Unicorn workers are consuming 100 percent of many of the cores on an 8 core host while this query is running. Other than the upgrade, there have been no changes. Any ideas where to begin debugging this?