In case someone comes here in the distant future.
Maybe one day this will be fixed, until then I added some sensors using the integration platform that seem to work okay.
- platform: integration
source: sensor.asuswrt_upload_speed
name: asuswrt_upload_integral_total_mbit
unit: Mbit
unit_time: s
round: 0
method: left
- platform: template
sensors:
asuswrt_upload_integral_total_gb:
friendly_name: "Upload total"
value_template: "{{ (states('sensor.asuswrt_upload_integral_total_mbit')|float / 8000) | round(1) }}"
unit_of_measurement: GB
- platform: integration
source: sensor.asuswrt_download_speed
name: asuswrt_download_integral_total_mbit
unit: Mbit
unit_time: s
round: 0
method: left
- platform: template
sensors:
asuswrt_download_integral_total_gb:
friendly_name: "Download total"
value_template: "{{ (states('sensor.asuswrt_download_integral_total_mbit')|float / 8000) | round(1) }}"
unit_of_measurement: GB