First of all, Jackson Yee is out of tune in part because he is not prepared enough. If you have made enough preparations before, singing a song should not be out of tune. As a singer, there are two reasons why he is not fully prepared before performing: First, he may be too busy to practice. Second, he didn't pay attention to the Mid-Autumn Festival party, so he didn't practice enough.
And Jackson Yi doesn't sing much now. He spends most of his time filming or doing other things. Therefore, singing seems unskilled and even out of tune. However, at the Spring Festival Evening, we can see that Jackson Yi didn't lip-synch. Compared with other lip-synching stars, Jackson Yi is more honest and frank, and he is a real person.
It is also possible that some people think it is a problem with the live recording equipment. Singing and recording songs by yourself is very different.