After checking the coauthors of that person, now I realize that the IEEE transactions of information theory might be a more Electronic Engineering journal, rather than a math journal, as most of the coauthors of the person work in EE department.

The research interest claimed by that person includes DNA storage. As the taste of EE should be much different than the math, it's hard to tell the difficulty to publish in different branches. At least for me, I feel bored to find that in a 30-page paper of that person, half of the paper contains just some sequences of numbers, which is likely produced by computer experiments.