The phrase "a complicated issue which" is correct and usable in written English.
It can be used when introducing a complex topic or problem that requires further explanation or discussion.
Example: "The report addresses a complicated issue which affects many communities across the country."
Alternatives: "a complex matter that" or "a challenging topic which".
This is a complicated issue, which has sparked much discussion.
This is a complicated issue, which is why it gets little attention in the mainstream press.
Asked how Tlass managed to escape such close scrutiny, the friend said: "That is a complicated issue, which it would be better for him to explain in person".
A spokesperson for the Sunday Times told the BBC: "The headline and the first sentence of the article over-simplified a complicated issue, which we regret.
It unearths a complicated issue, which tripped up Supreme Court Justice Ruth Bader Ginsberg as she called Kaepernick's approach "dumb and disrespectful," and our own famed basketball coach Roy Williams has finally warmed to, yet East Carolina University band members are facing a different response for their participation.
The more complicated issue, which may prove decisive, has arisen over ballots where the voter made an indentation with the stylus, creating a dimple but no perforation.
Making jokes on a talk show and drawing simple analogies for complicated issues — which he did with great skill as a candidate — were a way to reassure and befriend viewers.
These boys have serious and complicated issues which will not easily be solved, but we try to make a connection with them; get to know them and then slowly some of them amaze us with their gifts and abilities.
Furthermore, we discuss other complicated issues which are not considered in [18], such as sensitivity to noise.
These are complicated issues, which makes it increasingly important for organizations to regularly train employees on the ever-evolving threat landscape so that they are aware of what could put the organization at risk.
You want to guide them so they learn how to tackle their problems so they can move on to more challenging and complicated issues, which grows them and their business.
