Issue: button-card Not Working on iOS 18.3 (WebKit 605.1.15)

[sekonicpr]

Description

After updating to iOS 18.3, the button-card custom card in Home Assistant fails to load properly in both:
• Home Assistant Companion App
• Safari (and other WebKit-based browsers like Chrome)

The issue does not occur on iOS 18.1.1 but appears after updating to 18.3. Other users on iOS 18.3 do not have this issue, so it may be device-specific.

Devices Affected
• iPhone 16 Pro Max running iOS 18.3

What I Have Tried
• Verified that only one button-card resource is present in Settings → Dashboards → Resources
• Cleared Safari/Companion cache and website data
• Force closed and restarted Home Assistant Companion App
• Tested in Safari, Chrome, and HA Companion App (all fail)
• Reinstalled button-card in HACS
• Tested with a new, clean dashboard with only a simple button-card
• Tested on another iPhone running iOS 18.1.1 . Mac and PC (works fine)
• Verified that some users on iOS 18.3 do not experience this issue

Expected Behavior

The button-card should load normally, as it does on iOS 18.1.1 and non-iOS devices.

Actual Behavior
• Button-card does not render.
• The dashboard does not load correctly.
• No errors related to missing resources appear, suggesting the script is loaded but not executing properly.

Looking for:
• Confirmation from other users on iOS 18.3 experiencing this issue.
• Any workarounds to make button-card work on iOS 18.3.
• Input from the button-card developer on possible compatibility issues with WebKit 605.1.15.

[willoma]

I just updated my iPhone 13 Mini to iOS 18.3 (22D63), with 605.1.15. It works as expected, I do not have this issue.

[sekonicpr]

It breaks my head because I have no idea what could have happened that the rendering is different now with Safari 18.3