The phrase "a low key problem" is correct and usable in written English.
It can be used to describe an issue that is not very serious or is being treated with a relaxed attitude.
Example: "While it may seem concerning, it's really just a low key problem that can be resolved easily."
Alternatives: "a minor issue" or "a small concern".
As Baltimore County executive and governor, he backed anti-discriminatory public accommodations and open-housing laws and cultivated an image as a "low-key problem solver," the New York Times reported.
At 60, Sebelius is a popular two-term governor of a Republican-dominated state, and her reputation as a low-key problem-solver marks a contrast with Clinton.
The addition of spam links to a webpage is a comparatively low-key problem.
Martin Jones, 65, a retired special needs teacher and a member of Kirklees United Against Fascism group said that on one level he wasn't surprised by Jo Cox's murder because of what he called a "persistent and low-key" problem with fascism in the area.
It was a low-key exit reflecting problems that Mr. Bremer, and perhaps any American, could not resolve.
With Mr. Obama being attacked by Republicans for being too soft on China — and with many Americans blaming China for some of the economy's problems — a low-key approach to China creates political problems.
It was this quote, tucked away in a lengthy Vox article about Chase's career, that got everyone worked up: "We were in a tiny coffee shop, when, in the middle of a low-key chat about a writing problem I was having, I popped the question.
Groups in both states have based their proposals on models in place in Florida and Nevada, where the process has helped relieve problems in a "low-key way," according to Larry Simms, the president of the alliance and a consultant to co-op and condo owners.
To avoid political problems in Taiwan, Acer has traditionally taken a low-key approach in the mainland.
He comes across as a low-key hero reluctant to admit that he may have long-range health problems.
