OK -- I think I found the problem
In V10, Personal Profiles Setup Options, under the Notes tab I have the following:
Note 1: Member No.
Note 2: Occupation
Note 3: Moved from
Don't know what those were set to originally. My very unreliable memory seems to think that I may have swapped the original Note 1 and Note 3 labels, but not the data in the fields (i.e., sure enough! in V10 the member's number is in the field labeled "Moved from"). If this is a true memory and not something I have manufactured, then I guess I thought the data would automatically follow the label swap.
At any rate, looking at V11 Personal Profiles Setup Options, the data came over from V10 in the same format/sequence: Member No., Occupation, Moved from and the data that was in the (possibly user-modified?) Moved from field is, in fact, the member's number.
So, I guess I'll go into the setup and switch the labels to match the data.
Sorry for the false alarm.
*Still* learning... and gratefully so!