Perhaps because Weaver sets a line-height in the global CSS? Don’t know.
I tried with 2020 theme, and the typography options were even more different – but no line height.
Somethinkg theme related where only newest themes seem to allow that. But Weaver is definitely designed before the block editor. It does have a bunch of generateed CSS that attempts to change some of the default Block Editor styling to match the Weaver settings, but it is just not easy to keep up with all the Block Editor changes.