Is this question based on inspection bias? This table describes the positive corona tests in all three open ports of country X, in two different days, plus for the total positive for all people entering the country via those three ports:
Day 2     Day 1      Port
1.7%      1.4%        A
0.7%      0.4%        B
0.9%      0.2%        C
-------------------------
1.2%      1.3%   Total entering the country

How is it possible that although the proportion of the corona positive tests, for each port, were higher in Day 2, but Day 1 has a higher proportion in the total!
What paradox is this?

It is because the number of tested people can be different.
Imagine that on Day 2, 99% of your tests were done in Port C, and on Day 1, 99% of your tests in Port A. Then you would have on Day 2 roughly 0.9% and on Day 1 roughly 1.4%, which would even bee more "strange" than your actual data.
