Probably the washing machine.. is stressing the seams a little. You can keep washing it though.. in fact, please do.
Here's what you can do about it... Fabric store.. or sometimes Target/walmart... It's called Liquid stich.. aka Fabric glue.
Pull out your pockets... run a line down the seams. With a handy able-eyed helper (little kid).. fill in any gaps in the seams with the Liquid stich.
Problem solved! Until the fabric glue deteriorates that is....
My down comforter will stab me with quills sometimes... I just pull the feather out and hand over to my puppy for ingestion... No mess!