I've found that with UN-altered Males, that the irregularity of marking may depend on if he senses a viable mate in the area. Females go in and out of heat, the wind changes... Ha, lots of factors
So, when he senses the Female, he's going to react. It's natural
One thing I've found that helps is...
Make sure you take him out for walks, where he can mark "his" territory outside. This frequently can "move" the advertisement to a more convenient place for you, and still fulfill his need.
