I'm losing my mind trying to fix this problem, so any help would be appreciated!
As you can see in the images below, when I convert my ebook from its original EPUB into an AZW3 via Calibre, there are extra spaces inserted into these IM conversation sections (and only those, for some reason.) I've came at it from every angle, even checking that there's no irregularities with these parts in the ebook's HTML coding, but there doesn't seem to be any explanation for why this is happening or any way to stop it from happening.