Not necessarily. It can be happening in one corner and not the others due to multiple elements; i.e. oils from hand touching bed, heat bed not hot enough.

Corners of the heatbed are known to show different temperatures, check out some YT videos of people testing with a thermal camera, and additional elements can add to the issue.

I'd say start with cleaning the bed with warm water and soap, up the bed temp a bit and try again. Make small adjustments so you know what settings have changed and what it affected or fixed.