been pulling my hair out over this for two weeks. flying a M300 with the P1 and every single map i do the eastern edge of the ortho is noticeably softer than the rest. GCPs are placed pretty evenly across the site, overlap is set to 80/70, and the processing report in pix4d shows good keypoints across the whole thing. sun angle shouldnt be the issue because ive flown at different times and same problem.

the site is about 40 acres, mostly flat with some tree cover along one edge which happens to be roughly the east side. could that be it? like the trees messing up the reconstruction along that edge? or is there something else i should be checking. i feel like ive looked at every setting and cant see what im missing

trees along the edge will absolutely do this, the matching algorithm struggles with vegetation because the features keep changing between images - leaves move, shadows shift, that kind of thing. what i usually do is add a buffer zone to my flight plan so im capturing well past the tree line, like extend your grid another 50-60m beyond the actual site boundary. gives the reconstruction something solid to anchor to before it hits the vegetation. might not fix it completely but should help a lot

check your camera calibration in the processing report too, sometimes if the P1 lens cal is off it'll show up worse toward the edges of the mosaic. also what altitude are you flying at? i had somethign similar once and it turned out i had a slight overlap miscalculation because i forgot to account for the actual terrain height vs the takeoff point and one side of the site was effectively lower overlap than the rest. probably not your issue but worth double checking