In a language forum, I came across this contention by a native speaker:
People who have kindly given beds to visitors mustn't forget to send me details of their expenses. - CORRECT
The people who kindly gave beds to visitors mustn't forget to send me details of their expenses. - CORRECT
But this is wrong:
The people who have kindly given beds to visitors mustn't forget to send me details of their expenses.
Is it true? If it is, do you have any explanation of it?