I've read a couple of threads on a few of forums about this, and I see people say 'is yet to..' doesn't make sense. But then I see and hear:

"The best is yet to come." or
"The most exciting part is yet to come."

And the same examples mentioned above with "...has yet to come" not so much. However, examples such as:

"He has yet to receive the message"

Where 'has' is used, cannot be used with 'is'. Why? I don't understand why 'has' and 'is' are not interchangeable.

There are many more COCA citations for 'Has yet to' (3,200) than for 'is yet to' (400). However, for '... yet to come, the figures are 'has', 53; 'is', 180.

Both are acceptable.
Whilst it's normally "X is yet to..."

He has yet to receive the message
He is yet to receive the message

are both correct to me. Of the two, 'has' can give a feeling of being a little more overdue than 'is', but I wouldn't take that as a rule.

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"He has yet to receive the message."

This can also be understood as "He hasn't received the message yet."

Can it be understood as "He isn't received the message yet."?

That should clarify it for you.

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MustAsk"The best is yet to come."

That is a different case. In "He has yet to come", "come" means "arrive". In "the best is yet to come", "come" is part of an expression, "yet to come", meaning "in the future". You can't just do blind samplings and expect valid results.