How to express the concept of "invisible" typos

Typo blindness is an informal term. A Google search of the quoted pair yields 411 hits, so it might not be common, but it is out there.

The brain will often fill in missing or incorrect information without us realizing it. Perhaps the most famous example is filling-in visual blind-spots using the surrounding information.

This type of data correction is sometimes referred to as interpolation (see this paper as an example). In mathematics, it means to estimate data values based on surrounding data. With text, the brain is able to fix many mistakes without us being consciously aware of them.

There was a meme that made the rounds a while back based on this. It was based on the idea that people can easily read text even when the letters have been scrambled in a certain way. The phenomenon was informally referred to as Typoglycemia.

See this for a more scientific response to the meme.

Chabris and Simons (they of the studies on invisible gorillas on baskedball courts and such) call this the "illusion of expectation." Our brains see what we expect: the words we intended to place there.

This is an aspect of inattentional blindness ( https://en.wikipedia.org/wiki/Inattentional_blindness#Expectation ), or perceptual blindness.

I would suggest this a sub-division or perversion of the well-known idiom 'seeing is believing', in that perhaps 'not seeing is not believing'.

Typically the user will only see what they want to see, despite possible overwhelming evidence to the contrary.