Fast forward works only in windows mode

hello folks, i have a problem with fast forward: it works only in windows mode, if i set fullscreen nothing happens.

My configuration: CPU: Intel J1900 with integrated GPU Bay Trail OS: ArchLinux 64bit with Linux 5.4.13 Version: retroarch 1.8.4-1

My retroarch.cfg: https://pastebin.com/0BBvYkfW

I have tried to remove VSYNC but i haven’t solved.

EDIT: if i active THREAD VIDEO it works also on fullscreen, but thread video is highly unstable and often retroarch crash.

EDIT2: i have tried to set VULKAN at driver video. now fast forward works also on fullscreen but it is more slow than gl+windows mode.

SOLVED: from last retroarch version (1.8.5-1) fast forward also works in full screen mode, finally! Thanks.