I previously wrote about what cross-grinding is and why it’s not always bad. Here is a photo of one of my skates showing the distinctive marks left by cross-grinding.
If the cross-grinding wheel is too coarse (like the one I used with my Ferodowill skate holder), these can keep the blades from gliding nicely or worse, catch the ice and cause a fall. I discovered this when I took my Ferodowill-sharpened Jones skates out on the ice. As long as you smooth them out (e.g., by stoning the blade), they’re nothing to worry about.