When someone writes a title with the wrong letter cases ex: "my Title", is this considered a typo? If not, what is the name of this error?
A typo is unintentional mistyping, in contrast to other mistakes where you believe what you have typed is correct but it isn’t. Some examples:
you mean to type t but accidentally type T,
you typed the correct capitalization in a title but your software autocorrects it, to force the wrong formatting, and you fail to notice and prevent it.
When you mistakenly believe that it should be a T but are wrong (according to an accepted standard, or even just the opinion of your audience) that is not a typo, but a more culpable mistake. It's not a typing error.
If we didn’t make the error ourselves we don’t know if it is a typo or a misunderstanding of style, spelling, etc. However, we often make assumptions and call things typos if it seems likely that they are.
“Uprgading to 6.0 from 5.8” would be called a typo since the author is assumed to have understood how to spell “upgrading” but accidentally swapped two letters.
Capitalization that an observer sees, and believes to be an error of style, is more likely to be called a “mistake” not a “typo” when the observer can’t imagine how the mistake could have arisen just in something like a slip of the fingers on the keyboard.