User profile icon (avatar picture) disappears in login screen after system resume from suspension

This problem started to happen since the system update on 13/8 for the stable branch. My user profile icon (the avatar picture) always appears as it should in SDDM, except when the system resumes from suspend. I can't find any thread talking about this issue, nor any guideline of troubleshooting such issue on ArchWiki. Not sure what's going on there. Hope someone could please enlighten me.
Here's my system information.

System:    Host: Tu-PC Kernel: 4.19.69-1-MANJARO x86_64 bits: 64 compiler: gcc v: 9.1.0 Desktop: KDE Plasma 5.16.4 
           Distro: Manjaro Linux 
Machine:   Type: Desktop Mobo: ASRock model: X299 Gaming K6 serial: <filter> UEFI [Legacy]: American Megatrends v: P1.80 
           date: 05/27/2019 
CPU:       Topology: Quad Core model: Intel Core i7-7740X bits: 64 type: MT MCP arch: Kaby Lake rev: 9 L2 cache: 8192 KiB 
           flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 68760 
           Speed: 800 MHz min/max: 800/4500 MHz Core speeds (MHz): 1: 800 2: 800 3: 800 4: 800 5: 800 6: 800 7: 800 8: 800 
Graphics:  Device-1: NVIDIA TU104 [GeForce RTX 2080] vendor: Gigabyte driver: nvidia v: 435.21 bus ID: 01:00.0 
           Display: x11 server: X.Org 1.20.5 driver: nvidia resolution: 3840x2160~60Hz 
           OpenGL: renderer: GeForce RTX 2080/PCIe/SSE2 v: 4.6.0 NVIDIA 435.21 direct render: Yes 
Audio:     Device-1: Intel 200 Series PCH HD Audio vendor: ASRock driver: snd_hda_intel v: kernel bus ID: 00:1f.3 
           Device-2: NVIDIA vendor: Gigabyte driver: snd_hda_intel v: kernel bus ID: 01:00.1 
           Device-3: Logitech Webcam C930e type: USB driver: snd-usb-audio,uvcvideo bus ID: 1-1:2 
           Sound Server: ALSA v: k4.19.69-1-MANJARO 
Network:   Device-1: Intel Ethernet I219-V vendor: ASRock driver: e1000e v: 3.2.6-k port: f000 bus ID: 00:1f.6 
           IF: eno1 state: down mac: <filter> 
           Device-2: Intel I211 Gigabit Network vendor: ASRock driver: igb v: 5.4.0-k port: d000 bus ID: 03:00.0 
           IF: enp3s0 state: down mac: <filter> 
           Device-3: Edimax type: USB driver: rtl8814au bus ID: 5-2:2 
           IF: wlp2s0u2 state: up mac: <filter> 
Drives:    Local Storage: total: 2.71 TiB used: 1.40 TiB (51.6%) 
           ID-1: /dev/sda vendor: Intel model: SSDSCKKW480H6 size: 447.13 GiB 
           ID-2: /dev/sdb vendor: Samsung model: SSD 860 EVO 500GB size: 465.76 GiB 
           ID-3: /dev/sdc vendor: Seagate model: ST2000DX002-2DV164 size: 1.82 TiB 
Partition: ID-1: / size: 423.26 GiB used: 111.48 GiB (26.3%) fs: ext4 dev: /dev/sda1 
           ID-2: /home size: 1.79 TiB used: 949.29 GiB (51.8%) fs: ext4 dev: /dev/sdc1 
           ID-3: /opt size: 457.45 GiB used: 371.06 GiB (81.1%) fs: ext4 dev: /dev/sdb1 
           ID-4: swap-1 size: 16.10 GiB used: 0 KiB (0.0%) fs: swap dev: /dev/sda2 
Sensors:   System Temperatures: cpu: 32.0 C mobo: 30.0 C gpu: nvidia temp: 49 C 
           Fan Speeds (RPM): fan-1: 874 fan-2: 2080 fan-3: 2705 fan-4: 966 fan-5: 864 gpu: nvidia fan: 0% 
           Voltages: 12v: N/A 5v: N/A 3.3v: 3.30 vbat: 3.15 
Info:      Processes: 236 Uptime: 19m Memory: 15.67 GiB used: 2.29 GiB (14.6%) Init: systemd Compilers: gcc: 9.1.0 Shell: bash 
           v: 5.0.9 inxi: 3.0.36

SDDM and suspend/lock are 2 different things. They have no relation to each other.

Your lock screen is coming from your 'look and feel' theme.

Thanks. I change the title. I'm away from my computer at the moment so will check it later once I'm back home. Any advice that where I can start? The user icon seems all normal in the user manager.

I am not sure. I suppose we would start with 'what theme are you using?'.

[ they may identify the icon source in different ways ... I think I vaguely remember setting that myself somewhere at some point .. when we talk tomorrow I will try to help more ... but for now I give the example of /usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/lockscreen/* ]

I'm not sure why theme would cause any problem to the user icon (the avatar picture) but I use the default breath theme and breath icon.

The user icons look normal in the account manager and login screen.

However, after the system resume from suspend, the login screen becomes like this:

Here's the content of the lockscreen folder under my Plasma look-and-feel theme:

ls -la /usr/share/plasma/look-and-feel/org.kde.breath.desktop/contents/lockscreen/
總計 52
drwxr-xr-x  2 root root  4096 Jun 12 19:41 .
drwxr-xr-x 13 root root  4096 Jun 12 19:41 ..
-rw-r--r--  1 root root   584 Jun  2 19:23 config.qml
-rw-r--r--  1 root root   528 Jun  2 19:23 config.xml
-rw-r--r--  1 root root  2638 Jun  2 19:23 LockOsd.qml
-rw-r--r--  1 root root  2139 Jun  2 19:23 LockScreen.qml
-rw-r--r--  1 root root 16353 Jun  2 19:23 LockScreenUi.qml
-rw-r--r--  1 root root  3365 Jun  2 19:23 MainBlock.qml
-rw-r--r--  1 root root  5971 Jun  2 19:23 MediaControls.qml

Hope this information help.

Same problem.
The lock screen avatar comes back after restarting plasma, maybe something goes wrong with plasma on resume?

restart plasma:

killall plasmashell; plasmashell > /dev/null 2>&1 & disown

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