Replacing 16th digit to 0 despite formatting to text first

Cutting and pasting a table with headers that has one column of numbers that is 16 digits long results in 16th number being replaced with a zero.
I tried formatting the entire table to text before pasting, still leaves strange format I cannot change.
These numbers will never need to have any calculations performed on them ever.
This table is the same as others except for the length of this one column in this instance all the numbers are 16 characters long.