Series markers disappearing

[JezShed]

Hi all,
I've created a PMDX file that has a chart with 2 series plotted on it.
The markers on Series 2 don't seem to stay enabled after I save the file.
I've encountered this problem before on a different file that I had created from scratch. I must admit that I'm not sure if that problem had a specific cause/solution so I was surprised that the problem appeared on a completely new file today.
By the way, the second series includes deliberate "noise" which can be visualised by holding down F9 (when the markers are displayed anyway!).
The missing markers happens with both XLSX and PMDX file formats.
Can you reproduce it?
Thank you!
Jez of the Shed

PlanMaker NX Universal (rev S1502.0808) 64bit