Hello,
As it turned out, the problem was appearing only in Chrome, even after I cleared the cache. All other browsers were unaffected. I still have to figure out why does it happen, but this is not a big deal now 🙂 Thank you very much for your kind help!
Thank you for your reply, but, unfortunately, it didn’t help. I still get duplicate posts.
Thank you so much, but none of the advices listed there fixed the issue.
