The phrase "a complicated issue that" is correct and usable in written English.
You can use it when introducing a complex topic or problem that requires further explanation or discussion.
Example: "The report addresses a complicated issue that affects many communities across the country."
Alternatives: "a complex matter that" or "a challenging topic that".
"This is a complicated issue that is being worked through with the parties," he said.
Clinician burnout is a complicated issue that has fortunately been receiving much needed attention around the country.
The firm's abrupt reversal highlights the continuing potency of same-sex marriage as a complicated issue that has scrambled traditional political calculations in Washington.
Neither Fehr nor Bettman would discuss specific areas under negotiation, but Bettman called pensions a "complicated issue" that was "still a work in progress".
But in tactics worthy of Sir Humphrey Appleby from Yes Minister, the he has spent the last three years saying that it is a complicated issue that needs to be examined with care.
Again, that's a complicated issue that will be different for every person in this business.
"Well, I think this is a very complicated issue that needs a long-term congressional fix," Trump responded to Easton, an author and Fortune columnist.
Fathers' rights is a huge complicated issue that is gaining traction – few would argue that a genuinely strong, loving, consistent paternal presence isn't crucial to a child's development.
Why did Hatoyama make this promise in the first place, given that the relocation of the Futenma base is a thorny, complicated issue that has been stalled for the last 14 years?
Abortion is back in the headlines with stepped up attacks on Planned Parenthood and Pope Francis giving all priests the power to forgive what the Catholic Church deems a "grave sin". Abortion is a contentious and complicated issue that involves science as well as personal ethics and, to some, theology.
With 10 days to go before President Mikhail S. Gorbachev arrives here for a summit meeting with President Bush, the United States and the Soviet Union face a half-dozen complicated issues that must be resolved before they can declare an agreement in principle on a treaty slashing long-range nuclear weapons.
