The boat her and Jack were on....

[Quarepants]

Just heard this on a news report on the radio. To my ears that is incorrect and it should have been: the boat she and Jack were on...

But as said on a previous thread this is often how people type on mn. I would have thought a journalist would get it right.

It doesn't sound correct to me either. I would agree with your version. But so much on news and TV these days is incorrect.
My greatest irritant at the moment is the incorrect use of 'What' and 'Which' at the beginning of questions on quizzes....

Yes of course it’s wrong.
Remove ‘and Jack’ from that part of the sentence which leaves ‘the boat her was on’
Clearly, this is incorrect and should be ‘the boat she was on’.
Obvs, ‘was’ and ‘were’ would alter in that sentence.