This is still don't fixed n Resolve 15.1.1
Dear developers please take attention to this problem! It worked well in Resolve 14 but you destroy things in Resolve 15 and still don't fix it.
Resize mode "Sharper" in Settings:
Edit Page XY 0.5 px transform produce = 1 pixel black frame edge on rendered image
Color Page Node sizing Pan/Tilt 0.5 px node transform = 1 pixel black frame edge on rendered image
Color Page Input sizing Pan/Tilt 0.5 px node transform = 1 pixel black frame edge on rendered image
Resize mode "Bicubic" in Settings:
Color Page Node sizing Pan/Tilt 0.5 px node transform = 1 pixel black frame edge
Color Page Input sizing Pan/Tilt 0.5 px node transform = NO pixel black edge.
Edit Page XY 0.5 px transform = NO pixel black edge.
But If you essentially select "Force sizing to highest quality" in render settings there is always 1 pixel black frame edge on rendered image with ANY previous settings.
BTW, don't you thinking about some kind of dedicated OFX plugin or some kind of setting button in RAW tab to fix Cross Hatching? This can make workflow way simpler.
P.S. There is a huge thread about this problem, Cross Hatching Wont Go Away viewtopic.php?f=2&t=51936 Setting Pan/Tilt 0.5 px is the ONLY way to fix it yet.