Hello! I believe we fixed the issue Fix Uptime tests reverse logic by buger · Pull Request #635 · TykTechnologies/tyk · GitHub
So basic idea that it did not properly work with "failure_trigger_sample_size": 1 in tyk.conf
It continues sending traffic to the host until next health check.
We did not decide yet if it will be included into next patch release (and if there will be more patch releases), or in the upcoming 2.4 release.
Thank you!