I'm having a similar problem, I think. I'm adding my info to this thread, since I think it's the same. If it should be a new separate thread, please let me know or move it, and apologies.
My sensor / code sent some erroneous data at one point last night. I manually deleted those entries from the Feed, but it seems one data point still appears in the graph.
I saw your suggestion in another post to "only show RAW data" and to try changing the time period, but if the RAW data trick worked, I couldn't tell since it then only shows the most recent 640 data points (and the problem is older than that) and changing the time period didn't seem to help. As this data are my local barometric pressures, having this one data point
way out of range makes the resulting graph pretty useless as it compresses the Y axis line so much it's now basically a flat line.
I see other odd behavior when trying to edit the blocks and save the new layout. I've tried clearing my browser cache and restarting the browser, even logged in with a different browser, can't really seem to help anything. (macOS 11.16.1, Safari 15.1, Firefox 95.0.2).