question of responsibility; issue of liability
Used when discussing who should be held accountable or where the blame lies, often in formal or serious contexts.
The question of responsibility for this accident has not yet been resolved.
The politician's remarks escalated into an issue of accountability.
責任 is the general term for responsibility or duty, while 責任問題 specifically refers to the question or issue of where responsibility lies.
問題 is a broad term for problem or issue; 責任問題 narrows the focus to problems concerning responsibility or liability.
Compound of 責任 (responsibility) and 問題 (problem, issue).