RetroArch crashes when getting an achievement with fastforward on

Description

There's games where I enable fast-forward to get through the slow loading screens (we are talking PSX here), and I've encountered this bug now many, many times and it's getting really annoying. Basically, if I unlock an achievement with fast-forward enabled, there's a very high chance my emulator will freeze and close. I checked the logs with Verbose enabled and the very last line simply states that I unlocked the achievement. This also happened to me once without fast-forward, so I don't know what gives. This happened to me on many games now, and with both Beetle PSX HW and Duckstation cores.

Expected behavior

Unlock the achievement with fast-forward on (or not) and resume playing.

Actual behavior

RetroArch has a very high chance of crashing on me when unlocking an achievement with fast-forward enabled.

Steps to reproduce the bug

1. Get ready to meet the requirements for an achievement.
2. Toggle fast-forward.
3. Game crashes.

Bisect Results

This first happened to me when I installed Beetle PSX HW core around two weeks ago. I didn't even have fast-forward mode on when it crashed to me on Tenchu as soon as I got an achievement. Now it's started happening much more often with Duckstation.

Version/Commit

Latest Stable.

• RetroArch: [version/commit]
  1.9.12.

Environment information

• OS: Windows 10.
  Here I attach one of the logs from when the game crashed on me as soon as I got an achievement.

retroarch__2021_10_23__14_59_45.log

Start by reviewing the attached retroarch__2021_10_23__14_59_45.log and reproducing the crash on Windows 10 with RetroArch 1.9.12, fast-forward, and the Beetle PSX HW or Duckstation core. Trace achievement handling alongside fast-forward behavior; done means unlocking an achievement no longer crashes or closes the emulator, with or without fast-forward.