Q&A not working for streaming datasets

[otw09]

I have created 3 streaming datasets and been using REST API to post data to them. I enabled historical data analysis and created 3 reports respectively. Then I pinned the 3 visuals (1 for each streaming dataset) to 3 separate dashboard pages. When I try to use Q&A on them, only one of the 3 dashboards works. The other two keep showing "We weren't able to load suggestions right now. Please try again later." Any idea?