The "quickFind" feature and Html renderer are not compatible.
Indeed, one of the column of the Grid Scheduler has a custom renderer (see screenshot); when typing on the keyboard to search and highlight corresponding element is carried out, then at a certain point the outcome shows (see second picture) the detail of the renderer itself, instead of the value of the column.
The "quickFind" feature is set like this :
features: {
quickFind: true,
.....