the domain api.example.com is accessed over https, it set a cookie named 'uid', and secure flag of 'uid' default to true(browser do it).
and the subdomain m.api.example.com is accessed over http, it also set 'uid' cookie, and secure flag default to false.
when I first access api.example.com, then access m.api.example.com, the 'uid' cookie of m.api.example.com was blocked.
the warning in chrome (F12 -> Network -> Headers -> Set-Cookie):
The Set-Cookie was blocked because it was not sent over a secure connection and would have overwritten a cookie with the Secure attribute.
chrome has this problem, my version is 88.0.4324.96. Firefox is ok.
the subdomain can't access host only cookie of parent domain, why blocked?