MacBook Messages unread after reading them on iPhone 16

When I read texts in my Messages app on my iPhone 16 (iOS 18.6.2), they still show as unread in the Messages app on my MacBook Air (Apple M1 chip, MacOS Sequoia 15.6.1). How can I get my MacBook to sync so that the messages show as read once I've read them on my iPhone?

I have tried going into the Messages part of iCloud on my phone and clicking Sync Now, but that doesn't do it.