STP artifacts when using Depth of Field

Unity’s STP upscaling filter is quite impressive. However, I’ve noticed that it causes significant artifacts in areas where depth of field blurs the image. The artifacts appear as shimmering, MPEG-like blockiness, and overall unstable pixels.

Is this a limitation of STP or is there a way to fix it on my side?

Additionally, I’ve observed that when the frame rate drops below 60 FPS, the quality of the image produced by STP seems to decrease. I suspect that this is expected behavior, as fewer frames are available to reconstruct the image?