Why don't DDE links automatically update in Calc?

When I use a DDE link to link data from Calc to another Calc file, the data do not automatically update. Rather, I need to manually update the data by going to Edit > Links to External Files > Update.

When I link Calc data to a Word file, the data update automatically in Word when I change the data in Calc.

I am puzzled by this behavior. Surely it should be the same in both cases. What am I missing?

I have tried this in LO 6.2.7,, and 6.3 Beta and don’t see a relevant bug report.