Translating/Editing 2nd language changes original texts (BUG)

I think there is a bug somewhere.

I have a bilingual site (English/German) that is due to go online on Tuesday, Spetember 13th. The problem is when I go to edit the German page (whichever, Home, Imprint etc.), the text on the English page takes on the text that I just placed on the German page.
The pages are showing as /en or /de and this corresponds to the particular menu.

For example, if the original English page with /en has
Contact
You can contact me…

and I edit the German page to read
Kontakt
Sie erreichen mich…

and ‘update’, the German page is fine, but the English page will read:
Kontakt
Sie erreichen mich…

If I edit the English page back into English, English will appear on the corresponding partner page.

I have long since disassociated translations, so I don’t quite understand why the pages are mirroring the changes.

I could have my website up and running for tests already were it not for this problem. I need a full fix, but could also use a temporary solution for Tuesday. Should I just turn off polylang and lingotek until it gets fixed? Would my pages and menus still stay in place and be serviceable by users?

Regards
Kimberley