It is interesting. If the rails are the segmented kind, it’s smart to leave a small space between the rail ends for expansion.
These rails are probably the continuous kind, which are basically rolled out for miles on end, with only a few breaks.
Apparently they are indeed continuous welded rails, and also apparently they weren’t laid correctly (there is a way to lay them that prevents heat kink). Jointed rails survive on only a few busy urban railways nowadays (NYC I think is one), and they always left expansion space.