history-graph flickering and disappearing lines if values stayed the same for longer durations

[RubenKelevra]

Checklist

• [x] I have updated to the latest available Home Assistant version.
• [x] I have cleared the cache of my browser.
• [x] I have tried a different browser to see if it is related to my browser.
• [ ] I have tried reproducing the issue in safe mode to rule out problems with unsupported custom resources.

Describe the issue you are experiencing

In Chrome and Firefox graphs which show values which haven't changed for a longer duration will flicker on and off in the horizontal portions of the lines.

Chrome:

https://github.com/user-attachments/assets/d5e04c54-578a-42bc-8c19-6c6b1dd7151d

Firefox:

https://github.com/user-attachments/assets/b197b49c-b5bb-45f0-9172-f9df69d70a2f

Describe the behavior you expected

No flickering

Steps to reproduce the issue

1. Create a history graph
2. Have values which do not change over a longer time span
3. See flickering on each update of the graph, with disappearing lines

What version of Home Assistant Core has the issue?

2025.3.3

What was the last working version of Home Assistant Core?

2024.x

In which browser are you experiencing the issue?

Chrome 130.0.6723.174 / Firefox 129.0.2

Which operating system are you using to run this browser?

Arch Linux

State of relevant entities

Problem-relevant frontend configuration

type: history-graph
entities:
  - entity: sun.sun
  - entity: sensor.light_s_temperature_left_room
  - entity: sensor.adaptive_lighting_light_temperature_selection
  - entity: input_number.light_temperature_delta_left_room
  - entity: sensor.presence_left_room_presence_left_room_outdoor_color_temperature
  - entity: sensor.presence_left_room_presence_left_room_left_room_color_temperature
hours_to_show: 12

Javascript errors shown in your browser console/inspector

Additional information

No response