New Quick Access Toolbar Hide & Unhide Rows & Columns Icons Appeared, Then Disappeared

This is a very minor complaint, but I use about 35 Quick Access Toolbar commands, most of which have icons.  However, a few, most notably the Hide & Unhide Rows and Columns commands, had never previously had icons, until they appeared for the first time briefly this past weekend, which I thought were pretty cool, and then they disappeared when I got back from out-of-town on Wednesday.  Anyone from MS know what's going on with these?  Again, not a big deal, but very strange.  Thanks.