Having DDC/CI detection issues with different USB-C adapters on Linux

I'm experiencing a challenging issue with DDC/CI communication between my laptop running Ubuntu Linux and two external monitors connected via a USB-C to HDMI adapter (hub).

While DDC/CI functions perfectly when using a direct HDMI connection, it fails to work through my USB-C to HDMI adapter.

Interestingly, a friend's identical adapter model (Anker 555) successfully enables DDC/CI communication on their setup, which makes me wonder whether or not the adapter works is down to luck.

Setup Details:

• Laptop OS: Ubuntu Linux, kernel 6.5.0-17-generic
• CPU: Intel i5-12500H
• GPU driver: i915
• USB-C Hub 1: Anker 555 USB-C Hub (8-in-1). I have one of these myself, which doesn't work with DDC. My friend has an identical one which does work (can change brightness etc).
• USB-C Hub 2: Anker 332 USB-C Hub. This one does not work with DDC.
• External Monitor: 2x Dell SE2422HX, connected via:
  • Direct HDMI (works with DDC/CI)
  • USB-C hubs outlined above

Troubleshooting Done:

1. Confirmed both monitors support DDC/CI (Have been able to use ddcutil, change brightness etc…).
2. ddcutil detects the monitors correctly but reports "DDC communication failed" for the setup with the "bad" adapter.
3. No firmware updates available for any of the adapters.
4. Here is the ddcutil detect -verbose output to compare when the two adapters are connected. Display 1 would be the one connected to the "working" adapter and the invalid display is the one that doesn't. In this case both adapters are the Anker 555:

Display 1   I2C bus:  /dev/i2c-13      DRM connector:                      card0-DP-1      Driver:                             i915      I2C address 0x50 (EDID) responsive: true       Is eDP device:                      false      Is LVDS device:                     false      /sys/bus/i2c/devices/i2c-13/name    AUX USBC1/DDI TC1/PHY TC1      PCI device path:                    /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-DP-1/i2c-13   EDID synopsis:      Mfg id:               DEL - Dell Inc.      Model:                DELL SE2422HX      Product code:         41418  (0xa1ca)      Serial number:        53D5WB3      Binary serial number: 808863825 (0x30364851)      Manufacture year:     2021,  Week: 16      EDID version:         1.3      Extra descriptor:              Video input definition:    0x80 - Digital Input      Supported features:         DPMS standby         DPMS suspend         DPMS active-off         Digital display type: RGB 4:4:4 + YCrCb 4:4:4         Standard sRGB color space: False      White x,y:        0.313, 0.329      Red   x,y:        0.650, 0.333      Green x,y:        0.317, 0.615      Blue  x,y:        0.151, 0.060      Extension blocks: 1   EDID source: I2C   EDID hex dump:+0          +4          +8          +c            0   4   8   c   +0000   00 ff ff ff ff ff ff 00 10 ac ca a1 51 48 36 30   ............QH60+0010   10 1f 01 03 80 35 1e 78 ee 96 d5 a6 55 51 9d 26   .....5.x....UQ.&+0020   0f 50 54 a5 4b 00 71 4f 81 80 a9 c0 d1 c0 01 01   .PT.K.qO........+0030   01 01 01 01 01 01 02 3a 80 18 71 38 2d 40 58 2c   .......:..q8-@X,+0040   45 00 0f 28 21 00 00 1e 00 00 00 ff 00 35 33 44   E..(!........53D+0050   35 57 42 33 0a 20 20 20 20 20 00 00 00 fc 00 44   5WB3.     .....D+0060   45 4c 4c 20 53 45 32 34 32 32 48 58 00 00 00 fd   ELL SE2422HX....+0070   00 30 4b 1f 54 12 00 0a 20 20 20 20 20 20 01 0e   .0K.T...      ..   VCP version:         2.1   Controller mfg:      Mstar   Firmware version:    41.2   Monitor returns DDC Null Response for unsupported features: falseInvalid display   I2C bus:  /dev/i2c-15      DRM connector:                      card0-DP-3      Driver:                             i915      I2C address 0x50 (EDID) responsive: true       Is eDP device:                      false      Is LVDS device:                     false      /sys/bus/i2c/devices/i2c-15/name    AUX USBC3/DDI TC3/PHY TC3      PCI device path:                    /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-DP-3/i2c-15   EDID synopsis:      Mfg id:               DEL - Dell Inc.      Model:                DELL SE2422HX      Product code:         41418  (0xa1ca)      Serial number:        GHC5WB3      Binary serial number: 808928849 (0x30374651)      Manufacture year:     2021,  Week: 16      EDID version:         1.3      Extra descriptor:              Video input definition:    0x80 - Digital Input      Supported features:         DPMS standby         DPMS suspend         DPMS active-off         Digital display type: RGB 4:4:4 + YCrCb 4:4:4         Standard sRGB color space: False      White x,y:        0.313, 0.329      Red   x,y:        0.650, 0.333      Green x,y:        0.317, 0.615      Blue  x,y:        0.151, 0.060      Extension blocks: 1   EDID source: I2C   EDID hex dump:+0          +4          +8          +c            0   4   8   c   +0000   00 ff ff ff ff ff ff 00 10 ac ca a1 51 46 37 30   ............QF70+0010   10 1f 01 03 80 35 1e 78 ee 96 d5 a6 55 51 9d 26   .....5.x....UQ.&+0020   0f 50 54 a5 4b 00 71 4f 81 80 a9 c0 d1 c0 01 01   .PT.K.qO........+0030   01 01 01 01 01 01 02 3a 80 18 71 38 2d 40 58 2c   .......:..q8-@X,+0040   45 00 0f 28 21 00 00 1e 00 00 00 ff 00 47 48 43   E..(!........GHC+0050   35 57 42 33 0a 20 20 20 20 20 00 00 00 fc 00 44   5WB3.     .....D+0060   45 4c 4c 20 53 45 32 34 32 32 48 58 00 00 00 fd   ELL SE2422HX....+0070   00 30 4b 1f 54 12 00 0a 20 20 20 20 20 20 01 e9   .0K.T...      ..   DDC communication failed

Questions:

1. Has anyone encountered similar variability in DDC/CI functionality between identical adapter models?
2. Are there known workarounds or tools to enable DDC/CI communication over a USB-C to HDMI connection on Linux?
3. Could this issue be related to firmware differences within the adapters, and if so, is there a safe way to clone firmware from a working adapter to another?