So I have realized through my traffic reports that both the redirects and the 404s have exponentially increased since the last 2 weeks. Over the weekend, I realized that also many of my post and page URL slugs have been changing too (!)
After a lot of costly research, I found the latest version of 1.4.3 / TranslatePress Developer is responsible for this, and I had to revert back to 1.4.1 for those critical issues to get partly resolved.
The most infuriating part is that TranslatePress didn't send any emails to all of its paying users to warn about those issues. We had to find out ourselves after our website's SEO went down the drain.
Anyway, in case you have the same as me, here's what's causing this.
