I made a simple macro that would simply concatenate (using &) two values and directly copy them into another cell.

I did not declared a variable for it, I just wrote this

wsO.Cells(b, 2) = wsI.Cells(a + 1, 1) & wsI.Cells(a + 1, 2)

(I later declared a variable as String equal to wsI.Cells(a + 1, 1) & wsI.Cells(a + 1, 2) and the result is the same)

Being wsO and wsI different workbooks.

Everything seems to work, until I check some values and the following happens:

In some of the resulting values (some are fully numeric and some alphanumeric) the last digits are rounded to 0, for example:
wsI.Cells(a + 1, 1) wsI.Cells(a + 1, 2) wsO.Cells(b, 2)
6705935 000011288 6705935000011280
7220390 000RSM069 7220390000RSM069
7220390 000RSM070 7220390000RSM070
34547272 000000777 34547272000000700
43986229 000000776 43986229000000700
71699014 000RSM072 71699014000RSM072
71699014 000RSM074 71699014000RSM074
71750058 000000781 71750058000000700
800024702 000000462 800024702000000000

Is this an Excel VBA bug? Or is there a way to correct it?

Thanks,

Daniel