As noted here, there can be a lack of coordination between you and your horse Roach when it comes to summoning him. Like Tycho, I admit to bossing my horse around all the time in The Witcher: Wild Hunt; also, to be honest about it? It’s not always Roach’s fault. I will insist on summoning my horse and then running away from him, because I want to get to the objective and I’m caught up in the moment of the chase. Roach will still follow me; which shows some dedication and professionalism on his part. I should be more grateful for that.
…Look, it’s an immersive game, OK?