Evening-Truth created a dedicated page in the prompt library to complain about the response quality of the Z.AI Coding Plan:
Claim: After subscribing to the z.ai coding plan, the author "often, if not permanently" saw a massive drop in response quality; using the same batch of test calls, the author compared z.ai with OpenRouter and found the difference "too large to ignore."
Speculation: High-volume calls from subscribers may be routed to heavily quantized versions or distilled 7B/14B models.
Sources cited:
r/ZaiGLM https://www.reddit.com/r/ZaiGLM/comments/1rki1v0/ ("Is GLM-5 assigning quantized models to high-usage users?", 6 months ago)
r/SillyTavernAI https://www.reddit.com/r/SillyTavernAI/comments/1roxv8a/ ("glm_quality_via_subscription_or_paygo")
Key points from the cited r/ZaiGLM post (opened and checked during this collection): u/Super_Product_9470 reported that high-volume users on legacy subscriptions (without a weekly quota cap) frequently saw GLM-5 enter reasoning loops, produce incoherent answers, and appear to be routed to a quantized or lightweight model; several commenters (long-time subscribers and heavy users) confirmed the same phenomenon, while others attributed it to context length (degradation reportedly begins near 80k–100k tokens).
Author's position: "Subscriber calls may be re-routed to a heavily quantized or distilled version ... this is not a good way to do business."
Important boundary (must be noted): The Reddit evidence cited by the author (including r/ZaiGLM 1rki1v0) explicitly concerns GLM-5 Coding Plan quality issues (around February 2026, before the release of GLM-5.2). The dates shown on this page also predate the release of GLM-5.2. Therefore, this material is a continuing community complaint about the quality of the Z.AI Coding Plan service and cannot directly prove that GLM-5.2 itself was downgraded; it should only be treated as a service-level risk signal.
Direction corroborated by "06-Reddit-PoeAI-GLM-5.2 quality decline discussion": hosted or subscription channels may experience quality fluctuations unrelated to the model's capabilities; when an anomaly occurs, compare with another channel.
Evidence level: Personal experience plus secondhand community reports, with no controlled measurement; the author claims to have made comparison calls but has not disclosed the data.
"if you have a subscription to the z.ai coding plan you will often, if not permanently see a massive dip in response qua… This is a necessary excerpt; read the original source for full context.
"It's possible subscriber calls are being re-routed to a heavily quantized version or a distillation of 7B maybe 14B."
"Either way... that's not how good business is done."
GLM-5.2