Webpage asset transitions briefly flash another page in rotation #2954

Summary

When rotating between multiple webpage assets, Anthias briefly flashes/flickers a different page during every transition. The scheduled asset eventually displays correctly, but there is a visible one-frame/brief flash of another asset between transitions.

Environment

• Anthias version: v2026.5.1 (b9095c3)
• Device: Raspberry Pi 5 Model B Rev 1.1
• Asset type: webpage assets
• Browser/player: default Anthias viewer/player
• Assets are local HTTP pages served from another LAN/Tailscale address
• All assets are reachable and enabled

Asset setup

Current rotation:

1. Welcome - http://100.64.0.17:8088/welcome.html - 20s
2. Calendar - http://100.64.0.17:8088/calendar.html - 30s
3. Weather - http://100.64.0.17:8088/weather.html - 30s
4. DAGTech - http://100.64.0.17:8088/dagtech.html - 30s

All are configured as:

• mimetype: webpage
• nocache: true
• skip_asset_check: true
• refresh_interval_s: 60
• enabled and reachable

Actual behavior

On every page transition, the display briefly flickers/flashes one of the other configured pages before settling on the next scheduled page.

Example: while transitioning from one webpage asset to the next, a different page from the rotation appears briefly, then the intended page appears.

Expected behavior

Transitions between webpage assets should either:

• switch directly from the previous asset to the next scheduled asset, or
• show a neutral/blank transition frame,

but should not briefly show an unrelated asset from the rotation.

Why this matters

This is very noticeable on a digital signage display, especially with visually distinct pages. Even a very short flash makes the display look unstable or like the wrong page is being shown.

Notes

• The issue persists after rebooting the Anthias device and after the signage assets come back up.
• The pages themselves render correctly when opened directly in a browser.
• The issue appears specific to the Anthias asset transition/playback behavior rather than the web pages themselves.
• No custom transition effect is intentionally configured.

Happy to provide more diagnostics or test a patch/workaround if helpful.