On-screen caption disappears early (~7-8s) despite longer original cue duration

Bug
1

Hi, I’m seeing a consistent timing bug with the on-screen subtitle overlay on YouTube (auto-generated captions).

Platform: YouTube (Chrome extension)
Language: Turkish (auto-generated captions)

Problem description:
When Language Reactor’s on-screen subtitle box is active, each caption line disappears after roughly 7-8 seconds, even when the original sentence is clearly longer and should stay visible for 10-15 seconds. The next caption then appears and also gets cut short after a similar duration. This creates a repeating pattern where I never get to finish reading a sentence before it’s replaced.

Interestingly, the sentence list in the side panel (transcript view) does NOT have this problem — full sentences stay visible there with no early cutoff.

When I disable Language Reactor entirely, YouTube’s native captions display and transition normally, without this early-cutoff behavior. This suggests the issue is specific to how the LR on-screen overlay renders/times the original auto-caption cues, rather than an issue with YouTube itself.

Steps to reproduce:

  1. Open a YouTube video with Turkish auto-generated captions
  2. Enable Language Reactor’s on-screen caption overlay (not the side panel)
  3. Watch several consecutive captions
  4. Notice each one disappears well before a natural sentence would end (~7-8s), then the following one also cuts off early

Expected behavior: On-screen caption should stay visible for the full duration of the original cue/sentence, similar to how it behaves with LR disabled, or similar to how the side panel handles it.

What I’ve tried: Disabling LR (issue disappears — native YouTube timing is correct). Reinstalling the extension didn’t change the behavior.

Any insight into whether this is a known issue would be appreciated.This happens with all automatic subtitles.
Still, I’m including the link to the book I’m currently reading.

2

Hi everyone,

I wanted to share a temporary workaround and some technical observations regarding the known bug where subtitles disappear early (usually leaving the last 1/3 of the sentence unread).

I discovered that the root cause of this sync issue is directly tied to being logged into a YouTube/Google account, which changes how YouTube renders the subtitle lines.

The Workaround: If you log out of your YouTube account (but keep your Language Reactor extension active and logged in), the bug completely disappears. The subtitles stay perfectly in sync. Yes, you will have to deal with YouTube ads, but you won’t miss any text while listening to audiobooks or long videos.

The Technical Observation (Why this happens): I noticed a clear difference in how YouTube feeds the subtitles based on the login state:

  • When LOGGED IN (Bug occurs): YouTube tries to display the subtitles as a large 3-line block. Because it lumps so much text into one block, YouTube’s internal timer forces the block to disappear before the audio/TTS actually finishes reading it.
  • When LOGGED OUT (Works perfectly): YouTube changes its subtitle delivery. Instead of a 3-line block, it displays single-line subtitles sequentially (it shows one line, then updates to the next line, three times in a row). Because it feeds the text line-by-line, it never triggers the early disappearance and perfectly matches the audio.

It seems YouTube recently changed its subtitle rendering behavior for logged-in accounts, and LR is currently struggling to parse the timing of these new 3-line blocks.

I hope this distinction between the “3-line block” vs. “single-line” rendering helps the developers pinpoint the DOM/API change and patch the bug

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