Perf regression: json, kestrel-header-symbols, kestrel-header-symbols

| Scenario | Environment | Date | Old RPS | New RPS | Change | Deviation | StDev | Dependencies |
| -------- | ----------- | ---- | ------- | ------- | ------ | --------- | ----- | ------------ |
| json | Json Platform 10- Trends idna-amd-lin | 07/13/2026 10:10:12 | 170,569 | 160,277 | -6.03 % (-10,292) :thumbsdown: | -2.34 σ | 4,405.69 | Changes NameVersionDiff |
| kestrel-header-symbols | Kestrel Linux: Invalid Header 14- Trends cobalt-hosted-lin-azl3-28 | 07/12/2026 10:58:25 | 4,753 | 4,242 | -100.00 % (-511) :thumbsdown: | -3.30 σ | 154.77 | Changes NameVersionDiff Microsoft.AspNetCore.Antiforgery.dll `11.0.0-preview.7.26360.102` -> `11.0.0-preview.7.26360.111` https://github.com/dotnet/dotnet/compare/c98e79e96affb873c827e32c779a68b1368cc480...50dbab4de210e882172b07934e9666313b7065f1 Microsoft.AspNetCore.App `11.0.0-preview.7.26360.102` -> `11.0.0-preview.7.26360.111` https://github.com/dotnet/dotnet/compare/c98e79e96affb873c827e32c779a68b1368cc480...50dbab4de210e882172b07934e9666313b7065f1 Microsoft.NETCore.App `11.0.0-preview.7.26360.102` -> `11.0.0-preview.7.26360.111` https://github.com/dotnet/dotnet/compare/c98e79e96affb873c827e32c779a68b1368cc480...50dbab4de210e882172b07934e9666313b7065f1 |
| kestrel-header-symbols | Kestrel Linux: Invalid Header 13- Trends cobalt-hosted-lin | 07/13/2026 08:38:56 | 5,883 | 4,798 | -100.00 % (-1,085) :thumbsdown: | -2.87 σ | 378.61 | Changes NameVersionDiff |

[PowerBI Dashboard](https://aka.ms/aspnet/benchmarks)

@sebastienros

Start with the benchmark rows for json and kestrel-header-symbols, then use the linked PowerBI Dashboard to inspect the reported regression and compare the listed dependency commit range. Reproduce the affected scenarios if possible; done is identifying the cause and determining a validated correction for the reported performance loss.

Written by the indexing model from the issue text.