> Bug: If-Modified-Since is only really valid if you were served it as a Last-Modified value previously. Readers are inventing values, or are sourcing them from

> Bug: If-Modified-Since is only really valid if you were served it as a Last-Modified value previously. Readers are inventing values, or are sourcing them from the wrong layer of the stack. Don't do this. This sounds more like a server bug. The RFC mention this behavior, but with the caveat that it doesn't work as well. https://www.rfc-editor.org/rfc/rfc9110#field.if-modified-since https://www.rfc-editor.org/rfc/rfc9110#field.if-modified-sin...