Line chart time range adjusts to keep "now" in view

I gradually add data to a line chart as it arrives, but there's a significant latency (like hours or sometimes even more than a day) because the data comes over LoRaWAN via satellite. When I add the data points to a line chart, it adjusts to keep "now" in view, even though there's no way any data for "now" will ever be shown!

How can I get the chart to adjust the X-axis so that it only scales for the data actually being shown? (I'd hoped choosing "Last 0 hours" in the chart options might have an effect, but it didn't seem to.)

UPDATE: Further experimentation shows that, for some reason, this only seems to happen when points arrive out of order! I've done two tests, one where the points arrive in order and one where some do and some don't, and in the latter case, the chart scales to include "now" but in the former case, it only shows the time range of the data. That's very strange!