Yeah, last time I spend 18 hours mindlessly clicking the placard. I was even alone most of the time I spend there, then I saw some player running towards the placard so I quickly tried to buy the plot again but still no luck and they just relocated their house.

In total I've spend almost 70 hours in the course of several weeks and have always lost the plot to somebody relocating.

Relocating should have the same random timer as buying, that would fix this issue at least.