That's because your slave walks towards last click on the map. If you click 10 cells away and interrupt your own walking by using skill or getting hit, for example, on cell 5, you'll end up standing on cell 5, but your slave will still be going to cell 10, and will remain there until you click somewhere on the map again.
To prevent that you have to click on yourself or the cell next to you when you get stopped to make new destination for your alt, somewhere next to you. So yeah, learn to click more or learn how to make it useful. You can easily throw multiple alts into warp with that mechanics without alt tabbing between clients. Just click the warp and use some instant skill to stop your own char. Your alts should walk into the warp, no matter how many chars are following you. Pretty damn useful.
Or just find a party. Playing in party is much better than soloing with multiclients.
Edited by Psor, 26 February 2016 - 06:13 PM.