From the main menu, I right-click certain applications to add them to the desktop (they become KDE widgets). Within the menu, the application icons appear normal, and some appear normal when the desktop widget is created.
In the above image, the application icons for Kate and Irfanview appear as they do in the menu. LibreOffice Calc and Writer have a mini icon over a strange "grid". The icon background looks like a square that has been subdivided into roughly a 3x3 grid. The bottom corners and top left corner are black, the top right corner is oriented diagonally and black, and the remaining sort of "plus sign" is white. The tiny application icon sits on top of this distraction.
It appears that there is something unique in Mint's KDE implementation that results in selected desktop icons being created in this odd way. Any ideas as to the cause or solution?