Steps to reproduce:
1. Open a new spreadsheet.
2. Enter a url of your choice into any cell, for example in A1 http://bla.blub
and press enter
3. Walk to A1 with the cursor and press F2 to edit the cell.
4. When you now try to edit the url, you will notice you can't move the cursor
into the url but only to start or end of the url.
5. When you now think you can bypass this by going into the formular input line
to edit the url there as a workaround, you notice the same "cursor start to end"
behavior there.

=> So you are unable to edit the url of a cell. You can only delete the whole
string and re-enter the correct one.