The Blend node's primary input is drawn with line artifacts on certain pixel rows

The Blend node takes two inputs. But it is sampling the primary (top) input differently in a way that seems to cause artifacts, despite being identical inputs:


This is the bottom input which renders correctly (when Opacity is set to 0%):

This is the primary (top) input which displays the artifacts on some rows (when Opacity is set to 100%):

This can be reproduced by giving the 512x512 [Lena image](https://upload.wikimedia.org/wikipedia/en/7/7d/Lenna_%28test_image%29.png) layer graph (topology shown above) a transform of `834.1126644638082` by `553.0840346358935` and a uniform scale of `723.0485350346357`.