I suggest you report this problem to Apple on this via Number > Provide Numbers Feedback in your menu.
Meanwhile, it looks as if you your best bet is to restore the leading "zeros" after importing or pasting to Numbers.
One way to do that is via a script like the one below. It's easy to use.
- Copy-paste the script into Script Editor (in Applications > Utilities).
- Adjust the target length in the first line of the script to the length of your phone numbers (including the leading zeros).
- Insert a new column in Numbers and explicitly format its cells as Text.
- Select the cells in the "old" column in Numbers that contain the numbers you need to "fix".
- With those cells selected click the triangle 'run' button in Script Editor.
- Click once in the top cell of the new column in Numbers where you want the "fixed" values.
- Command-v or Edit > Paste and Match Style to paste the "fixed" numbers with the leading zeros restored.
- If all is well, delete the "old" column.
At first glance this looks complicated, but actually it's just a few clicks. There are also ways to restore the leading zeros with a formula, but that takes more work.
SG
property tgtLength : 10 -- change this as needed
tell application "Numbers"
tell front document to tell active sheet
tell (first table whose selection range's class is range)
set pasteStr to ""
repeat with c in selection range's cells
set paddedNum to "00000000" & c's value
set pasteStr to pasteStr ¬
& my strRight(paddedNum, tgtLength) & return
end repeat
end tell
end tell
end tell
set the clipboard topasteStr
display notification "Click once in Numbers cell, and command-v to paste."
to strRight(s, n)
try
return s's text -n thru -1
on error
return s
end try
end strRight
