I am interested in citing a paper. This paper has ~30 citations from others, which is respectable and indicates that a fair number of people have also found it worth discussing. However, a fairly prominent citation discussed in this paper is of an (in my opinion) low quality article from an undoubtedly predatory journal. My gut feeling is this is a minor issue and I shouldn't be concerned with citing the work as whole, and just do not pay any attention to the problematic citation; doing so wouldn't affect my planned work. However, I was wondering if there is something I have overlooked and should be concerned with before proceeding.
It is obligatory to cite works that you use in your research. This includes bad works, works with errors, works that have never been cited, works published in bad/predatory journals, and works that were never published.
When deciding to cite something, the first thing to ask yourself is, "Did I use this in my research?" If the answer is yes, you need to cite it. If the answer is no, you may or may not need to cite it.
When deciding if you should cite a paper, disregard a citation to a predatory journal in that paper.