DIY Doctor UK DIY Forums

Several boards of my 1 year old laminate floor have started to move apart after they were soaked when the kitchen tap leaked. There's about 3 gaps between the boards and the biggest one got to around 50mm, so pretty big. Initially I though the boards were shrinking but measured them and they weren't so must have just been moving back. At one end they go under the kitchen units and there's nothing to stop them moving. Not had any problems with any of the other parts of the floor though, just the ones that got wet.
Anyway, I eventually sorted it, pulled it up, knocked them back in and thought that was it but they've started moving apart again. They're not wet not as the leak happen months ago. Why would they still be moving and what's the best solution?
I probably should fix something up at the end under the kitchen units to stop them pushing that way but why would they still be moving apart anyway?

Thanks for any help