Gap between triangles that share vertices

I’m drawing relatively large triangles with the camera close by. On 1070 and 2080 hardware (driver 442.59) there’s a gap between these triangles, on an older 770 card this issue doesn’t occur. The two triangles are part of two separate triangle strips, but the vertex coordinates in the vertex buffers are exactly the same (verified with nSight).

Strangely, setting DepthClipEnable to false in the rasterizer state used to draw the triangles fixes the issue, even though they aren’t even close to intersecting the far plane.

I can provide an nSight capture of this issue.

The gap:

Identical vertex coordinates: