I always try to present a popover from a cell inside a tableView this way:
[myPopover presentPopoverFromRect:cell.frame inView:self.tableView permittedArrowD
I did come across this problem as well. A solution for me was to simply change the width of the rect returned by CGRect)rectForRowAtIndexPath:(NSIndexPath *)indexPath :
CGRect rect = [aTableView rectForRowAtIndexPath:indexPath];
//create a 10 pixel width rect at the center of the cell
rect.origin.x = (rect.size.width - 10.0) / 2.0;
rect.size.width = 10.0;
[self.addExpensePopoverController presentPopoverFromRect:rect inView:aTableView permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
This create a rect centred inside the cell. This way, the popover has more chances of findind a good spot to position itself.