VLOOKUP Not seeing all source links but find does

Problem linking values from one wookbook / sheet to anouther. Almost all
cells work fine but some do not, they do however if I copy/paste the lookup
value into a "search all sheets" and double click the cell in the source
sheet that contains the lookup value.

Example: Look up cell for destination file on sheet1 = 1234
Look up cell from source file on sheet2 = 1234

Both are formated as "text" but the vlookup data is not transfered until I
double click on the cell containing 1234 in the source file sheet2 then it
works fine until I update the file again.