New bug introduced in Origin 2025b.

1. New a worksheet and set columns A, B, C to row numbers.

2. Set colC column designation to Y-error.

3. Highlight columns A to C and create a line + symbol chart.

4. Ctrl+ double-click any error bar to create a special point.

5. In the PD of the special point, uncheck Directions and uncheck Plus.

6. Click Apply
   ==> Error bar still show both directions.

Fixed in Origin2026