Graphic issue with Beetle PCE Fast - Ys Book I&II - Playfield border doubled along bottome of screen

Using the Beetle PCE Fast core a graphic issue appears with Ys I&II. It's the only game thus far that I've noticed this issue. Sorry if this is the wrong way to go about reporting it. I've tried messaging on Facebook as well.

Description

Once you start the game and get past the intro and into gameplay there is a decorative border around the gameplay window. Part of that border is being doubled along the bottom of the screen, which isn't done on real hardware. I've checked Ys III, which uses the same screen layout and it does not do it on Ys III.

Expected behavior

Normally it would be completely black under the stats and health bar.

Actual behavior

As mentioned before, the border graphics are being duplicated along the bottom of the screen.

Steps to reproduce the bug

1. Select Beetle PCE Fast core
2. Start Ys I&II bin and cue file
3. Start game and press run to begin game

Bisect Results

Started within the last several core updates. This wasn't happening less than a year ago. Can't pinpoint exactly when it started.

Version/Commit

You can find this information under Information/System Information

• RetroArch: 1.6.7

Environment information

• OS: Windows 10
• Compiler: [In case you are running local builds]

I tried uploading pictures several times but it keeps throwing up an error.

Start by reproducing the issue with the Beetle PCE Fast core and the Ys I&II BIN/CUE files, then compare its gameplay border with Ys III and real hardware behavior. Confirm the duplicated bottom border and trace the relevant core rendering path. Done means the area beneath the stats and health bar is completely black without regressing the shared screen layout.