ep_dcp_other_items_remaining can't reach 0 after loading docs on build 7.1.0-1306

In our performance runs, the runs will wait until ep_dcp_other_items_remaining reaches 0 after loading docs. However, in several magma performance runs on build 7.1.0-1306, ep_dcp_other_items_remaining can't reach 0 for hours. These runs were aborted manually or after hitting the timeout threshold.

http://perf.jenkins.couchbase.com/job/rhea-5node1/1568/

2021-09-17T22:38:52 [INFO] ep_dcp_other_items_remaining = 1,207,713

2021-09-18T10:38:51 [INFO] ep_dcp_other_items_remaining = 756,406

http://perf.jenkins.couchbase.com/job/rhea-5node1/1571/

2021-09-18T17:54:44 [INFO] ep_dcp_other_items_remaining = 392,600

2021-09-18T20:58:20 [INFO] ep_dcp_other_items_remaining = 397,996

https://s3.amazonaws.com/bugdb/jira/qe/collectinfo-2021-09-19T035328-ns_1%40172.23.97.21.zip

https://s3.amazonaws.com/bugdb/jira/qe/collectinfo-2021-09-19T035328-ns_1%40172.23.97.22.zip

http://perf.jenkins.couchbase.com/job/rhea-5node1/1572/

2021-09-18T21:52:35 [INFO] ep_dcp_other_items_remaining = 392,340

2021-09-18T22:04:17 [INFO] ep_dcp_other_items_remaining = 391,212

https://s3.amazonaws.com/bugdb/jira/qe/collectinfo-2021-09-19T045917-ns_1%40172.23.97.21.zip

https://s3.amazonaws.com/bugdb/jira/qe/collectinfo-2021-09-19T045917-ns_1%40172.23.97.22.zip