Observing tearing artifacts on Roku-4 with 4k @ 60fps HEVC stream

I printed device information and I have copied the log below. I referred ifDeviceInfo to get device information.

*******************************************************************
*****************       Device Information       ******************
*******************************************************************
* GetModel: 4400X
* GetVersion: 177.20E04100A

* GetDisplayType: HDTV

* GetDisplayMode: 720p

* GetDisplayAspectRatio: 16x9

* GetDisplaySize: <Component: roAssociativeArray> =
{
    h:  720
    w:  1280
}

* GetDisplayProperties:
  width= 160
  height= 90
  Hdr10=false
  DolbyVision=false
  internal=false


* GetSupportedGraphicsResolutions:
ReslIndex[ 0]
    width= 1280
    name=HD
    preferred=false
    height= 720
    ui=false
ReslIndex[ 1]
    width= 1920
    name=FHD
    preferred=true
    height= 1080
    ui=true


* GetVideoMode: 2160p30

* GetModelDisplayName: Roku 4

* CanDecodeVideo INPUT:
  profile=high
  codec=hevc
  level=6.2
  CanDecodeVideo OUTPUT:
    level=<Component: roArray> =
[
    4.1
    5.0
    5.1
]
    updated=level
    result=false


* GetUIResolution:
  width= 1920
  name=FHD
  height= 1080

HDMI port connected check passed: true
HDCP 2.2 check passed: true
*******************************************************************

I have connected Roku-4 to a "LG 65EF9500" TV and all HDMI ports are rated as 60Hz on it. My question is: Why Roku is detecting video mode as 4K@30fps? Please observe "GetVideoMode" in the log.
Let me know if I need to check any additional settings.