The JS used to generate the DateTime picker for the "Search"/filter actions for any date time coluum will not accept sub-second precision - even if you manually type it in, the JS will "helpfully" parse and reformat the input by deleting the subsecond part.
- Browse -> Task Instances
- Expand "Search"
- Add a filter on a date column (Start Date say)
- Type/paste 2018-10-16 20:24:26.375717+01:00 in the box
- tab to move focus elsewhere
- See the value change to 2018-10-17 09:44:32!! (note different day and time!)
If you manually edit the URL then the original input is accepted fine.