Well, technically, it's completely useless to spam Repair since there's no chance involved at all, so if it doesn't work the first time, it won't randomly work later. But I get that players wouldn't know that and might think that they could get it to work eventually.
Now, fixing this issue would be quite annoying actually, since it's hard to track if it's the first time you try to repair HK at this "repair state". Of course, I could make it so that you only loose influence the very first time you fail any repair but that seems weird as well.
And finally, to me it actually makes thematic sense that if you keep trying to repair HK unsuccesfully over and over again that at some point he would refuse to be repaired again and have a lower and lower opinion of you, i.e., lower influence.
With all of that in mind, this does not seem like something worth fixing to me.