Statisctics Diagram: Logarithmic scale is not displayed correctly since 2025.2

[christian-schauer]

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

Since the statistics diagram overhaul in 2025.2, the logarithmic scale is not displayed correctly anymore as the lines for 0 or null values do not drop to 0 anymore:

Describe the behavior you expected

For all 0 or null values of a data series, the line in the chart should drop to 0. This worked perfectly until the recent overhaul of the statistics diagrams.

Steps to reproduce the issue

1. Create a dashboard with a statistics diagram.
2. Use time series data that has 0 values (e.g. like inverter production of a PV).
3. Observe the issue
   ...

What version of Home Assistant Core has the issue?

2025.2.3

What was the last working version of Home Assistant Core?

2025.1.4

In which browser are you experiencing the issue?

Google Chrome Version 132.0.6834.160 (also verified in latest Firefox version)

Which operating system are you using to run this browser?

Windows 11

State of relevant entities

Problem-relevant frontend configuration

chart_type: line
period: 5minute
type: statistics-graph
entities:
  - entity: sensor.wechselrichter_sud_string_leistung
    name: Süd
  - entity: sensor.wechselrichter_ost_string_leistung
    name: Ost
  - entity: sensor.wechselrichter_west_string_leistung
    name: West
  - entity: sensor.wechselrichter_garten_leistung_von_p1
    name: Garten
stat_types:
  - mean
logarithmic_scale: true
days_to_show: 1
hide_legend: false
card_mod:
  style: |
    ha-card {
      --graph-color-1: red;
      --graph-color-2: blue;
      --graph-color-3: orange;
      --graph-color-4: green;
    }

Javascript errors shown in your browser console/inspector

Additional information

No response

[MindFreeze]

smoothing probably has to be adjusted or turned off for log graphs

[MindFreeze]

may be a duplicate of #24229