It looks like in BryntumGrid.vue and BryntumGridBase.vue the columns prop changed from:
"@bryntum/grid-vue": "5.2.10"
columns : { type : [ColumnStore, Array, Object], default : undefined },
to
"@bryntum/grid-vue": "5.3.0"
columns : { type : [ColumnStore, Object], default : undefined },
and now it's throwing an error in the console because the columns prop is an Array of Objects. Was this change on purpose?