A libreOffice Chart has suddenly gone blank with only the titles and legend visible

I have a Calc spreadsheet of unit trust prices containing a chart on a separate tab. The sheet is updated monthly. This has functioned normally for over three years but after I added another row of prices today and went to the chart but this was blank except for the chart Title and Subtitle and the legend. How do I rectify this. Clicking in the chart area shows a selection box. Double clicking activated the chart for editing but still nothing is displayed.

I have just opened a different LibreOffice Calc sheet with four charts each on separate tabs. One of those charts has done exactly the same thing and is blank except for the titles and legend. The other three are displaying correctly. It seems that this is not an isolated incident and may be a bug. It may tie in with a recent update to Version: 6.4.0.3 (x86) as I last edited these two sheets in the previous version.

More information. I have just opened both spreadsheets referred to in my earlier posts using LibreOffice 6.0.7.3 running in Ubuntu Mate and all graphs are displaying normally. It seems like there may be a problem with 6.4.0.3.

Not an answer, but just to say that I had (almost) the same problem: updating to LO 6.4.3 made disappear about 50% of the charts in an Excel file saved with 6.1.X. I did not try with other files. I uninstalled 6.4.3 and installed 6.3.5: same issue. Only after uninstalling 6.3.5 and installing 6.2.8.2 all the charts re-appeared.

So, this is a major problem, I guess.

I am working on Windows 7 64 bits and LO 64 bits and Java 8 64 bits.