Reproduction instructions:

1. Make your display 1920x1080
2. Switch your LO UI locale to an RTL one, say Hebrew
3. Start LO Calc
4. Maximize the Window
5. Note the active cell coordinates (and maybe choose some cell to be active)
6. On the menus, choose דפים (i.e. Page), and toggle מימין לשמאל (i.e. Right-to-Left), to switch the sheet direction.
7. Set a cell on a different row and column to be the active cell

Expected result: 
At step (3.), the sheet should be LTR (otherwise change the default direction so that it is, and restart the procedure).
Before step (6.), there is a certain number of columns which are fully visible, and (at least on my system) no column which is partially-visible. After step (6.), even if some column becomes partially-visible, it should simply look like the column next to it - empty interior, no special patterns or coloring.

Actual result:
Step (3.) and before step (6.) - same as expected.
After step (6.), 
* a bit of an additional column is barely-visible, column W (this may or may not be a bug).
* The left edge of the visible part of the column W cell, on the row which had the active cell during the switch, has jagged blue coloring, reminiscent of the active cell border coloring - touching the scrollbar.
* Other cells in column W, but not all cells, have one or two black dots at the left edge of the cell, touchign the scrollbar - as though some content was being hidden by the scrollbar.

Will attach before-and-after screenshots.