Numbers Open Recent files missing after upgrading to 15.1

Numbers 15.1 does not appear to import Numbers 14.4's Recent Files list.

It only keeps track of files opening in 15.1

I assume this is either a) an oversight, or b) the fact you can have both 14.4 and 15.1 installed at the same time, and you might want to keep them separate. Either way, you can use the Numbers -> Provide Numbers Feedback menu to report it to Apple.

Does Numbers 15.1 limit the number of open files?

I opened 7 files and selected 2 others but they would not open and no indication that they were not being opened. So I returned to Numbers 14.5 to edit those spreadsheets after quitting 15.1. Then I quit 14.5 and was able to open those two in 15.1. Now I am able to open more files - currently 12 are open. I'm certain those 2 files that would not open at first with 15.1 had been edited using 14.5.

It (15.1) does not have the same recent files that were in the list using 14.5. 15.1 only has files opened while using 15.1.

I am having almost the same problem. Version 15.1 does not open the sheets (7 sheets in one doc) that I have in one of my 14.4 document. It only opens one sheet and not the latest. However it does open sheets in 2 other documents.