The main reasons the error in his 1905 paper has not been found before are that 1) many scientists accept Einstein’s equations as correct, and 2) the problem is hard to detect.

I think that part of the reason that the 1905 mistake hasn’t been previously discussed is because finding an objective way of detecting the problem has been elusive. In addition, even if one believes that an error exists; identifying the root cause requires one to review the time “function” as a function rather than an equation. Even after discovering Einstein’s 1905 mathematical error and knowing “where” it occurred, it still took me another year to understand “why” it occurred.

In his 1912 paper and Relativity book, the errors are again hard to find. Understanding why it occurs requires one to understand the mathematical definitions surrounding implication and equivalence. In this case, Einstein uses an implication association, but treats the equations as if they have been shown as equivalent. This is extremely subtle, but mathematically verifiable.

Fortunately, we can rely on objective mathematics rules to confirm Einstein’s mistakes, identify “where” they occur, and understand “why” they have occurred.