Hi forum!
I am running 5.9 and just updated with the last patch but still gets this problem. In grid style manager i have done 3 different styles and saved them, 100m,50m and 20m. When opening the manager it just blank rows but i can still choose them. I have tried to delete them and make new and then it worked for a while but now they are gone again. Its a video of the problem posted here also :).