A mixture of http and https in Matomo visit log

Hello everyone, I have an question about A mixture of http and https in Matomo visit log.
Our site has SSL certificate and there is no mixed content.Therefore, All of the URL are suppossed to be https.
But When I open the visit log in Matomo, I find some of the URL start with http. And i also found the following appearance.
When I mouse over the link that starts with ‘/abc/d’(without domain) , the detail shows the URL starts with http.
On the other hand,the link that starts with ‘www.example.com.com/abc/d’(with domain) will show the URL starts with https.