I only see one of your two gauges in the photograph. I'll surmise that there is a noticeable difference in the positioning of your two gauges relative to structures, trees, or other things that can interact with the wind.
As it happens I operate three gauges and routinely compare the results after rainstorms. One is a Davis VP2, one is a Rainwise, and one is a 4 inch plastic analog gauge that appears to me to be exactly the physical structure of the CoCoRaHS. My long-term observation is that slow steady rain with negligible wind gives almost identical results among the three gauges. Extremely high rain rate has the two tipping bucket gauges lagging behind, with the (bigger) Rainwise gauge lagging a bit more. But even a moderate amount of wind can lead to noticeably different results among three gauges. None of the three is out in the middle of a field hundreds of feet away from trees or structures. Instead they are along a fence which is only 10 to 20 feet away from my house, and the Davis is well under 30 feet from a fairly tall tree. I am pretty sure that even moderate wind interacts with the nearby features to create local variation in rain rate which is faithfully captured by the gauges and turns into noticeable differences in total from the same storm.