Thanks everyone for the comments, etc. One clarification: there was no Dock option to "Show Package Contents"; it was just happening.

Problem resolved! Tried various things which did not change the situation, then did a restart of the computer. Shazaam! Numbers documents in the Dock Documents Folder now open correctly. Go figure.


On a Mac since 1984.
Currently: 24" M1 iMac, M2 Pro Mac mini with 27" BenQ monitor, M2 Macbook Air, MacOS 14.x; iPhones, iPods (yes, still) and iPads.