It seems to me that this term is used mainly in Hong Kong education discussion. When you do a Google search, the document 4. 課程內容 is a good introduction to this approach. [Don't be intimated by the Chinese title, the article is actually in English.]
From the document:
(a) The issue-enquiry approach implies a learning/teaching methodology in which a learner searches for relevant solutions to a problem and can argue reasonably for and against the possible solutions. Its techniques encourage students to be inquisitive, to develop solutions by questioning and research and to find possible solutions for themselves.
(b) The approach centres on the development of skills that enable students to identify, investigate, understand, evaluate issues and offer solutions for them. Pre-determined positions on the part of students might be modified by discussion, and consensus may evolve but is not a necessary outcome. They should be encouraged and be given opportunities to gather essential information for these purposes. Strongly held, reasonable non-consensual views should be respected.
The following are some of the basic questions to be considered in order to make the issue-enquiry approach effective:
(a) What is the issue?
(b) Why does this issue arise?
(c) What areas are covered by this issue?
(d) What kinds of questions do students wish to raise about the issue?
(e) How might they obtain the basic information?
(f) How can they distinguish between facts and opinions?
(g) Are there different approaches to this issue?
(h) What possible solutions seem to arise from research and analysis?
(i) How viable are the alternatives?
This looks like a good approach to teach subjects which have no black and white answer.