My washer full of water even after use?

My daughter opened the door to my Beko WMB 10 washer & flooded the kitchen.
The washer hasn't been used since friday, but has been opened regularly to put the next load of washing. No water was present until today.
I tried the spin cycle & the drum goes round fine, I also checked the waste water pipe to see if there was a blockage.
I opened the front filter & that was full, when I tried another spin the filter was full once again.

Why was the filter full & how come the washer was half full after being opened previously.

Thanks for any help.