I work in a multi-cultural team: I'm employed directly by the company and based in Europe, but apart from me and another colleague, all the remaining team members are from a contractor and are based in Asia (I'm mentioning it since I believe this can play a role). We, the direct employees, are supposed to have a managing/ organizing role towards the outsourced colleagues. We are following an unorthodox Scrum.
There's a problem that is repeating itself. The colleagues from the vendor wait most of the sprint to signal a problem to me or assign me a task and then complain a lot that they can't progress on their task because they are waiting for my (or my colleague's feedback).
We have a good, competent team on our side, but we all have a lot on our plates and we normally do need 2-4 days to solve issues, unless that's something with priority 1, which is solved immediately or something planned.
So the colleagues don't signal an issue during the first part of the sprint and then create a blocker and stress they aren't able to move on because of lack of my or my colleague's reaction. It's about issues that are identified during their work, not assigned to me for the sprint, so they can't be planned.
E.g., someone is to create an automation that goes to a website and downloads a specific file. That's their main task for the sprint. They discover after the first week of the two-week sprint that they don't have access to the website. (Before you ask: we do have a sprint planning and ask every time whether all prerequisites, accesses, etc. to complete a story have been met.)
The reply "you just assigned me that yesterday evening, and I will reply in a due course" sounds defensive and hostile. But I'm not ok with being blamed for their lack of progress and user stories not being closed with a justification they lacked my feedback either. They should identify their problems earlier.
What's the best way to tackle that?