hm, not sure of the creation sequence of my site. I think I created first the Bulgarian version but in general that shouldn't matter, as the actual language is irrelevant.
Have you made sure that ~/home is the English translation of ~/начало? This is done through the Pages section of WP admin panel. All the settings should be identical except for the permalink, of course.
In my case my ~/home (or just the domain) page is the page Начало, i.e. the Bulgarian one and its English translation is ~/home-2.
All the translations of the content I did via the string translations.
I guess my first suggestion is to double check the translations of the pages and also the permalinks of each of them. It is very strange where this mismatch comes from.
How do your "URL modifications" settings of polylang look? Perhaps something there could cause it...
I am not much of a help but let me know of your progress.