[BUG]: Armored Core 2: Misaligned subtitle box border

[Berylskid]

Describe the Bug

Top border of subtitle box is displayed wrongly like stairs.

• Renderer and internal resolution don't matter. It occurs on both of Hardware/Software renderers.
• See GS Window Screenshots section. I uploaded visual comparison to there.

Reproduction Steps

1. Boot Armored Core 2
2. Start "NEW GAME"
3. Skip FMVs and then wait for loading
4. See subtitle box of the first mission's intro

Expected Behavior

Like on actual PS2, the top border should be flat instead of stair-shaped.

PCSX2 Revision

v1.7.5788

Operating System

Windows 11

If Linux - Specify Distro

No response

CPU

i5-8250U

GPU

MX150

GS Settings

No response

Emulation Settings

No response

GS Window Screenshots

PCSX2	PS2

Logs & Dumps

Here is a GS dump.
Armored Core 2_SLPS-25007_20240508203209.gs.zip

[refractionpcsx2]

Probably a preround thing (which the preround PR doesn't handle currently)

Tested the GS dump on my PS2 and confirmed it's just a GS issue.