Default refresh rate overridden by some core options

First and foremost consider this:

• Only RetroArch bugs should be filed here. Not core bugs or game bugs
• This is not a forum or a help section, this is strictly developer oriented

Description

In the Genesis-Plus-GX core, changing the interlaced mode option causes the refresh to be changed to 59.94Hz.

This results in stuttering if previously configured to run with 60Hz.

Expected behavior

Core to not override frontend settings.

Actual behavior

Core forces refresh rate change with no option to disable enforcement.

Steps to reproduce the bug

Set Refresh Rate to 60Hz

Disable Windowed Fullscreen

Enable Fullscreen

Start a game in the Genesis-Plus-GX core and set Interlaced Mode 2 Output to Double Field

Bisect Results

Commit cfcd0a7a0d06f47c1f5dce8690a6ef6ae1b76034

Version/Commit

Stable 1.9.12 and latest nightly 4b16b4f

All Genesis-Plus-GX core builds over the past few years exhibit the issue.

Environment information

Windows 11

Additional Info:

https://github.com/libretro/RetroArch/blob/4b16b4fe9a08ddaa63d03b0054cff74a7ecddaf1/retroarch.c#L10632

Changing 59.94 to 60.00 prevents issue.

Inspect retroarch.c around line 10632 and reproduce the issue with the Genesis-Plus-GX core using the listed fullscreen, refresh-rate, and Interlaced Mode 2 Output settings. Verify that changing the interlaced mode no longer overrides a frontend-configured 60Hz refresh rate, while confirming the existing reproduction no longer stutters.