Hidden service introduction point retries occur at 1 second intervals
Tor will try to reconnect to an introduction point up to 3 times. But rend_consider_services_intro_points() is called every second, which means that it uses up these retries very quickly, particularly if the connection fails quickly, like direct connections sometimes do on single onion services.
It might be more sensible to retry slightly more slowly.
On the other hand, maybe it's good that we fail fast and replace the introduction point.
This behaviour was introduced in commit 1125a487.