Size-transiton isn't animated

Platform

Manjaro x86-64

GPU, drivers, and screen setup

xf86-video-intel 1:2.99.917+908+g7181c5a4-1

name of display: :0.0
display: :0  screen: 0
direct rendering: Yes
Extended renderer info (GLX_MESA_query_renderer):
    Vendor: Intel (0x8086)
    Device: Mesa Intel(R) UHD Graphics 620 (KBL GT2) (0x5917)
    Version: 20.1.8
    Accelerated: yes
    Video memory: 3072MB
    Unified memory: yes
    Preferred profile: core (0x1)
    Max core profile version: 4.6
    Max compat profile version: 4.6
    Max GLES1 profile version: 1.1
    Max GLES[23] profile version: 3.2
OpenGL vendor string: Intel
OpenGL renderer string: Mesa Intel(R) UHD Graphics 620 (KBL GT2)
OpenGL core profile version string: 4.6 (Core Profile) Mesa 20.1.8
OpenGL core profile shading language version string: 4.60
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile

OpenGL version string: 4.6 (Compatibility Profile) Mesa 20.1.8
OpenGL shading language version string: 4.60
OpenGL context flags: (none)
OpenGL profile mask: compatibility profile

OpenGL ES profile version string: OpenGL ES 3.2 Mesa 20.1.8
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20

Environment

XFCE

picom version

vgit-3ecf9

Configuration:

backend = "glx";

glx-no-stencil = true;

glx-copy-from-front = false;

# animations
transition-length = 300
transition-pow-x = 0.1
transition-pow-y = 0.1
transition-pow-w = 0.1
transition-pow-h = 0.1
size-transition = true
spawn-center = true

shadow = true;
shadow-radius = 15;
shadow-offset-x = -10;
shadow-offset-y = -10;
shadow-opacity = 0.75;

shadow-exclude = [
    "! name~=''",
    "name = 'Notification'",
    "name = 'Plank'",
    "name = 'Docky'",
    "name = 'Kupfer'",
    "name = 'xfce4-notifyd'",
    "name = 'cpt_frame_window'",
    "class_g = 'firefox' && argb",
    "class_g = 'Firefox' && argb",
    "class_g = 'Conky'",
    "class_g = 'Kupfer'",
    "class_g = 'Synapse'",
    "class_g ?= 'Notify-osd'",
    "class_g ?= 'Cairo-dock'",
    "class_g ?= 'Xfce4-notifyd'",
    "class_g ?= 'Xfce4-power-manager'",
    "_GTK_FRAME_EXTENTS@:c",
    "_NET_WM_STATE@:32a *= '_NET_WM_STATE_HIDDEN'"
];
shadow-ignore-shaped = true;

inactive-opacity = 1;
active-opacity = 1;
frame-opacity = 1;
inactive-opacity-override = false;

blur-background = true;
blur-background-fixed = false;
blur-background-exclude = [
    "window_type = 'dock'",
    "window_type = 'desktop'",

    "window_type != 'normal'",
    "class_g = 'File-roller'",
];

fading = true;
fade-delta = 10;
fade-in-step = 1.0;
fade-out-step = 0.05;

fade-exclude = [
    "! name~=''",
];

mark-wmwin-focused = true;
mark-ovredir-focused = true;
use-ewmh-active-win = true;
detect-rounded-corners = true;

detect-client-opacity = true;

refresh-rate = 0;

vsync = true;

dbe = true;

unredir-if-possible = true;

detect-transient = true;
detect-client-leader = true;

wintypes:
{
    tooltip =
    {
        fade = true;
        shadow = false;
        opacity = 0.85;
        focus = true;

        blur-background = false;
    };
};

xrender-sync-fence = true;

blur:
{
    method = "gaussian";
    size = 21;
    deviation = 15;
}

Steps of reproduction

Maximize a window or snap it to the side (so it tiles to half of the screen).

Expected behavior

The window should smoothly transition between its currents size, and the new size.

Current Behavior

The window resizes instantaneously, and only its position change is animated.

Other details

I also tried out Phisch's fork. With it, the animated size transition works, but it has other problems (it lags horribly when dragging around windows right after size change).

jonaburg / picom

Size-transiton isn't animated #11