Example:
https://evergreen.mongodb.com/build/mongo_c_driver_ocsp_patch_f5b2f9557c6623b86a46e0db846ad0d233f93760_5f10ec5cd6d80a595b8e88aa_20_07_17_00_10_05

The failures are inconsistent. The "soft fail" test has the OCSP responder down, and expects connection to succeed. "Test 3" has the OCSP responder returning a valid response. I strongly suspect an issue with caching.

The attempt to clear the cache does not appear to work on those hosts, as this appears in the logs:

[2020/07/17 00:20:51.703] + find /Users/mci/profile/Library/Keychains -name ocspcache.sqlite3 -exec sqlite3 '{}' 'DELETE FROM responses' ';'
[2020/07/17 00:20:51.704] find: /Users/mci/profile/Library/Keychains: No such file or directory