The following is just my suggest, pls check it.

Can reproduce it with DEV300m37 on WinXP and Fedora

How to reproduce it
1 Open a new Clac document
2 Select any cell in the file, like *A1
3 Format - Cells, 'Format Cells' dialog opens, switch to 'Borders' Tab, set a
  number to 'Left' of 'Spacing to contents', e.g. 30mm. Meanwhile, make sure
  check 'Synchronize', OK
4 Double_click to edit A1
5 Double_click to edit A1 and enter some characters, e.g. '123456', set cursor
  another cell except A1

Result
At step 4, after double_click A1 and enter editing mode, pls pay attention to 
cursor's location, its left spacing is about 30mm, its top spacing is 0mm, it 
bottom spacing is about 60mm;
After step 5, the characters '123456' are shown in cell A1, but characters's 
showing spacing is inconsistent with the settings on the 'Format Cells' dialog.

Expectation
At step 4, in editting mode, just set cursor on the left top of the cell, 
shouldn't use the Left or bottom spacing
After step5, can adjust the cell's width to meet with the 'Spacing to contents'

Regards
Li Meiying