1.display.zul
2.select cell-data
3.select cell-refence
4.set G4 value = ='cell-data'!G1, it become 'percentage'
5.select cell-data
6.delete column E,F
7.select cell-reference
8.the value of G4 should be ='cell-data'!E1, and 'percentage' ,however it doesn't it is 0 and ='cell-data'!G1

NOTE: if you skip step 3, then it doesn't has such issue.