Binary sensor history is not rendered properly

[KrilYura]

Checklist

• I have updated to the latest available Home Assistant version.
• I have cleared the cache of my browser.
• 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

That yellow part is only shown when I hover over it

Here is a grey one in another day

For some reason those only appear when mouse is over them
First two images are from chrome, this one from safari

Seems like there is something wrong with rendering a week of binary sensor data

Describe the behavior you expected

I should see the whole bar filled with history data as it is at the right end

Steps to reproduce the issue

1. Open history of binary sensor
2. Select a week of data
3. Observe that only the right part of the bar it rendered
   ...

What version of Home Assistant Core has the issue?

2025.11.3

What was the last working version of Home Assistant Core?

No response

In which browser are you experiencing the issue?

Chrome, Safari, haven't tried others

Which operating system are you using to run this browser?

macOS 15.6.1 (24G90)

State of relevant entities

Problem-relevant frontend configuration

JavaScript errors shown in your browser console/inspector

Additional information

No response

[MindFreeze]

Does this only happen with this one sensor or others as well?

[envy]

I can confirm this also happening in Firefox on Windows 11.

Without hovering:

with hovering:

For me, its not every binary sensor. I suspect it has to do with the number of state changes.