Using `bslib` themes in `flexdashboard` disables lazy loading of pages

I have 3 tabs in my flexdashboard (using shiny runtime). When I use the default theme, everything runs as expected. When the app starts, it only runs the global code chunk and the code chunks related to the first page. When I click to select the second or the third page, the code chunks related to them would run (i.e. lazy loading of multiple pages).

However, when I use bslib to theme my flexdashboard, all code chunks are run when the app starts, which causes the start time to increase dramatically.

Is there a way to enforce "lazy loading" even when using bslib?