Created attachment 90640 [details]
Writer document with one chart, copied in Writer from Calc.
Create something like
time 1 2 3 4
length 2 4 6 8
ordered in a row.
Create a x/y chart in calc.
Copy this chart to writer. It would be shown right.
Save the wirter-document
Close LO, the reopen again. The chart in the wirter-document is shown right in all LO-version up to 18.104.22.168 rc. Since 22.214.171.124 rc Writer reads only the first 2 data-columns.
The bug has been gone in LO 126.96.36.199 rc and also LO 188.8.131.52.beta2. So I will close this bug as worksforme.