Interactions suddenly working incorrectly.in the Service

Definitely a bug. Visual-level filters are (supposed to be) explicity scoped to a single visualization, as the name implies. Brushing and linking should only be based on the currently selected axis category.

I'm able to reproduce the behavior you're seeing in the service.

Edit: Apparently the community forums are the official bug report medium for Service bugs now.

Repro steps:

1. Create a bar or column chart, chart1, with any category as the axis label, and some measure on values
2. Create a second chart, chart2, with months as the axis label and some measure from the same fact table on values
3. Add month as a visual-level filter to chart1
4. Apply a filter on chart1's visual-level filter to a single month
5. Select any bar/column in chart1
6. Observe chart2 being filtered to only the month in chart1's visual level filter

Edit2:

Confirmed identical behavior for chart1 as any column or bar chart (stacked, clustered, combos, waterfall), pie, donut, funnel, or treemap and chart2 as any visualization.