Tell me please what is the difference between the following sentences.
It is ok to add supplementary exercises to the main lifts. Just do it at the right time.
It is ok to add supplementary exercises to the main lifts. Just do it at a right time.
I did not ask which one is correct because I was listening to a podcast in which native English speakers used the indefinite article in the sentence. And it has really bewildered me because I thought that the definite article is always used before words like right or wrong. Could they make a mistake?