The phrase "a key issue during" is correct and usable in written English.
It can be used to highlight an important topic or concern that occurred within a specific timeframe or event.
Example: "Climate change was a key issue during the international summit last year."
Alternatives: "a significant concern during" or "an important matter during".
That is likely to be a key issue during Thursday's hearing.
Analysis: It is interesting that immigration, which was such a key issue during the election, gets such a brief mention.
With voters concerned about interest rates and house prices, the economy will be a key issue during the campaign.
Outside the Swan shopping centre, Julie Rowe told Ashdown that she was worried about development – a key issue during the byelection, with the Tories accusing the Lib Dems of voting through housing estates on green spaces.
A key issue during the lawyers' visit will be whether authorities should release to the public videos of the fatal shooting of 24-year-old Jamar Clark a week ago.
A key issue during the talks was how to respond to China, which has been sending ships to contest Japan's control of the group of uninhabited islands in the East China Sea known as the Senkaku in Japan and the Diaoyu in China.
The focus of this article is on a key issue discussed during the National Biogas Conference, hosted by the Southern African Biogas Industry Association (SABIA) on 5 March 2015: the lack of awareness and understanding of biogas as a form of energy in the general public, which hinders the expansion of this technology in this country [12].
The controversial Keystone XL pipeline will likely be a key issue discussed during the summit, with Canada's government pushing for the U.S. to approve the massive pipeline that would ship crude from the oil sands of Alberta to the Gulf of Mexico for refinement.
A key issue to emerge during the inquest has been the failure of the Home Office, the prison service and other agencies to share sufficient information about foreign national offenders who serve a prison sentence, as Yusif did, and are then considered for transfer to an immigration detention centre and deportation.
Each of Wilson's ten plays centers on a key issue for African Americans during that decade.
Given that participants were mostly older people, some of the economic impacts of chronic illness unique to younger populations--such as a loss of income due to inability to work and its consequences--were not raised as a key issue, hence not fully explored during the interviews.
