Smells of a DNS cache issue. Maybe libcurl is using its own resolver? I know at least it has its own in-process DNS cache that for example may not be activated

Smells of a DNS cache issue. Maybe libcurl is using its own resolver? I know at least it has its own in-process DNS cache that for example may not be activated by default with the easy API. Or that it can be compiled with c-ares support, etc.