Explain the signal for me.

Resurrecting an old post again but I have a peculiar problem that seems related but not sure if it’s an SM or AP issue. As you can see from the link test, there is a significant gap between the H and the V SNR but only on the downlink, and that is reflected in the speeds I’m getting. Is this a faulty SM or is the problem in the AP? It’s a PMP-450 900 MHz with a 12 db yagi.