If a table exists within the last blog section, the margin/gap between the above-located paragraph and the table itself is not applied. Tables in other H2s work just fine.
Here’s my custom CSS for the post: single template
I solved the problem by removing the -end suffix from my declaration, resulting in the margin appearing at block-start and block-end positions. I am unsure if I caused it by adding the block-end margin to the template stylesheet or if this is a bug.