Good evening Henry and welcome back!
Thank you for reaching out to us.
We are sorry to hear about the background colour of your calendar misbehaving.
I would love to help you with this topic.
As a first troubleshooting step, could you please provide us with your complete system information in a private reply using the instructions found in the following link?
https://theeventscalendar.com/knowledgebase/sharing-sys-info/
In the meantime, there are a couple of things I would recommend trying.
Under Events -> Settings -> Display, try different settings for Events Template to see if that changes anything.
In your theme’s style.css or Custom CSS section, try the following rule:
#tribe-events-content table.tribe-events-calendar {
background-color: white;
}
Let me know how that goes.
Best regards,
Geoff B.