Description:
XY Chart legend name and associated Range for name disappears when Calc document is saved and reopened

Steps to Reproduce:
1.Open attached document Some_generic_data.ods
2.Open sheet "Sorted"
3.Double click any chart, e.g. top left called 210 measurements
4.Right click it.
5.Select Data Ranges...
6.Select Data Series tab.
7.Select currently unnamed series called Series (not score)
8.Select Name
9.Click button next to range for name.
10.Select cell E57
11.Click ok
12.Now chart legend next to red dot displays "inverse score weighted avg x from 50 best samples"
13.Save the document.
14.Close LibreOffice Calc.
15.Open saved document Some_generic_data.ods by double tapping it in Windows explorer.

Actual Results:
There is no legend for second (red) series. see attached Actual.png

Expected Results:
There is legend for second (red) series "inverse score weighted avg x from 50 best samples". see attached Expected.png


Reproducible: Always


User Profile Reset: No

Additional Info:
Even before saving the file, if the Data Series... menu is recalled again after being closed Range for Name of Series being edited is already empty. Even though previously selected label for series is still correctly displayed on chart legend.
The same problem can be reproduced in this document for Chart "First 187 measurements" when I66 is selected for range for name.
The same problem can be reproduced in this document for Chart "Best 50 samples in 210 measurements" when E57 is selected for range for name.
The same problem can be reproduced in this document for Chart "Best 50 samples in 187 measurements" when I66 is selected for range for name.