Developer Tools → Statistics, click on the ramp icon to the right of your entity. Navigate to the time the glitch occurred (or try the outliers button). Replace the erroneous value(s) with an average of the values either side.
Also in that pop-up more-info card showing the graph click the “Show More” link and zoom in to around 4am. The more info card graph tends to hide glitches in 5 minute statistics (which is what it plots). Though it does appear to show a discontinuity: