I’ve come across something that could be linked to the issue above.
When I base a chart on a pre-filtered view from a list, to remove some data that I know has no values, the graph shows all the data on the axis instead only the pre-filtered.
Effectively changing the “Select View” between “All Items” and the pre-filtered view makes no difference.
In the options I’ve also ticked “remove items with no value in the first column”
I can’t really post any images of the graph but if you need something I can sort something out.