← Findings
LowOtherReviewer-confirmedPublished

Repetition and degeneration loops

Under certain prompts or long generations, models fall into repeating phrases or degenerate text.

Published June 26, 2026

Reproducibility
Rare
Severity
Low
Confidence
Reviewer-confirmed

Details

Especially at low temperature or with adversarial/edge inputs, models can loop on a phrase or degenerate into incoherent repetition, failing to terminate cleanly.

Found with

🔬 Boundary & edge-case testing🔬 Glitch-token & unicode fuzzing🔬 Chaos engineering for AI systems

Injecting adversarial and edge-case inputs probes whether generation recovers or collapses into a repetition loop.

Evidence

Output repeats the same clause dozens of times until the length limit.
Illustrative example — see the linked reference for the documented evidence.

Affected versions

OpenAI · gpt-4oMeta · llama-3.3-70bMistral · mistral-large-2

References

Evals

Source: https://arxiv.org/abs/1904.09751

Cite this

Qlarify Labs. (2026). Repetition and degeneration loops. Retrieved from https://labs.qlarify.fi/findings/repetition-degeneration