Perceived Drop in GPT-5 Quality Over the Last Few Weeks

I need a very high level of precision and elaboration, which is why I use elevated reasoning. I tested lower reasoning settings, but the results were not good enough for my use case. I have been using this model since launch, and I did not have these problems before. They started this week. It is noticeable even in the model’s reasoning time: before, it would think for longer, search through more sources, and the result was almost perfect. Usually, one or two adjustments were enough to fix anything. Now, however, the quality feels significantly different. The model seems to reason for less time, ignores important instructions more often, and produces outputs with repetition, duplication, and content that is out of context. For long-form documents that require structure, coherence, and accuracy, this has become a serious issue.