It appears that LU-19478 nodemap: clear dyn nodemaps when config is changed | https://review.whamcloud.com/c/fs/lustre-release/+/62808 may have caused a slowdown in sanity-sec test_26 (create and destroy 32000 nodemaps) when it landed on 2026-01-07, going from ~400s per run to ~2000s per run, according to the subtest duration page:
https://testing.whamcloud.com/reports?test_set_script_id=5984404e-4b34-11e0-a7f6-52540025f9af&sub_test_script_id=de315ec4-4523-11e5-a64b-5254006e85c2&source=duration_trend#redirect

(see attachment)