I am using Primefaces 10.x

Using the Schedule component like this :

<p:schedule id="schedule" 
    value="#{myBean.eventModel}" 
    widgetVar="myschedule" 
    minTime="08:30:00" 
    maxTime="16:30:00" 
    allDaySlot="false" 
    view="timeGridWeek" 
    slotDuration="00:15:00" 
    initialDate="#{myBean.initialDate}" 
    tooltip="true"/>

and

DefaultScheduleModel eventModel = new DefaultScheduleModel();
DefaultScheduleEvent<?> event = DefaultScheduleEvent.builder()
       .title("WORKSHOP : Virtual Suturing Workshop")
       .description("WORKSHOP : Virtual Suturing Workshop")
       .startDate(...)
       .endDate(...)
       .textColor("black")
       .data(...)
       .draggable(false)
       .build();
eventModel.addEvent(event);

as you can see, basically straight out of showcase and documentation. but this is what I see when previewing:

I have tried but have had no luck finding out a way to not make the schedule's tooltip transparent.

Any advice on where to look for a solution?