The phrase "a core issue in" is correct and usable in written English.
You can use it to refer to a fundamental or central problem within a specific context or subject matter.
Example: "The lack of communication is a core issue in the team's performance."
Alternatives: "a central problem in" or "a fundamental issue in".
A core issue in the case from its beginning in April 1989 has been the young men's videotaped confessions.
That question goes to a core issue in the criminal law regarding the responsibility of suppliers for the use of products they sell.
The decision set a less stringent standard: the evidence must be "of direct and important value in determining a core issue in the case" and "cannot reasonably be obtained elsewhere".
On migration – a core issue in many of Labour's heartlands – Smith said it was something "we need to be proud of" and that it was vital for services such as the NHS, highlighting the international nature of his own family.
Mr. LaRossa and other critics contend that the unions' electoral success contributes to the high cost of government in New Jersey, a core issue in a state where Gov. Chris Christie, a Republican, has clashed with labor and lawmakers over salaries, pensions, staffing and overlapping layers of government.
That MTR also owns a huge property portfolio is almost certainly a core issue in its involvement with Shenzhen.Back in 2004, as part of a strategic effort to expand beyond Hong Kong, MTR commissioned a report from a local university on transit systems in many of the world's largest cities, which observed that "railway investment is not financial viable on its own".
In January, Core Issues staged conferences in Belfast and London backed by Anglican Mainstream, entitled The Lepers Among Us.
Every one of the startups I've been involved with since have faced a core issue like this in some form.
Given the position that they have taken on a core issue of religious freedom in America, I cannot in good conscience keep that award..
Ban, who will step down at the end of the year after a decade in charge of the United Nations, has made action on climate change a core issue of his time in office.
A core issue of the anticipatory turn in social sciences are the so-called 'weak signals'.
