Having Trouble With ePSXe

[PityOnU]

Posted this over on ngemu, but that forum seems pretty dead, so I figured I'd repost here to see if any of the local wizards con help me out (or at least replicate the issue so I know I'm not insane).

I'm having trouble using Pete's OpenGL2 2.9 video plugin with multiple games (but the one I notice it most in is Harvest Moon: Back to Nature). Before I go any further, I'm using ePSXe 1.9.25, and below is my configuration for the video plugin:

Plugin: Pete's OpenGL2 Driver 2.9
Author: Pete Bernert
Card vendor: ATI Technologies Inc.
GFX card: AMD (ATI) FirePro M4000 (FireGL V) Mobility Pro Graphics
Resolution/Color:
- 1920x1080 Fullscreen - NO desktop changing
- Internal X resolution: 2
- Internal Y resolution: 2
- Keep psx aspect ratio: on
- No render-to-texture: •E
- Filtering: 0
- Hi-Res textures: 0
- TexWin pixel shader: off
- VRam size: 0 MBytes
Framerate:
- FPS limitation: on
- Frame skipping: off
- FPS limit: Auto
Compatibility:
- Offscreen drawing: 0
- Framebuffer effects: 3
- Framebuffer uploads: 2
Misc:
- Scanlines: off
- Mdec filter: off
- Screen filtering: off
- Shader effects: 0/1
- Flicker-fix border size: 0
- GF4/XP crash fix: off
- Game fixes: off [00000000]

While playing the game, everything renders perfectly and runs at 1080p60. However, the problem I'm having is that there is a strange horizontal line that loops through the screen (starts at the top, slowly drifts towards the bottom over a number of frames, and then starts back at the top again). The effect is very similar to screen tearing, and that's what I thought it was originally, but after messing with frame-limiting and vsync options in both ePSXe and my graphics card control application, I now know it isn't.

The issue does not happen with the software renderer, so I know it's something related to the plugin. Can anyone provide any insight as to what may be causing the problem?