I discovered that many duplicate strings started surfacing in my only supported language that doesn’t have automatic translations (Arabic).
Previously it was 80%+ translated, then that day it suddenly became only 50%+ translated, and the duplicates are why.
Here is just one example. As you can see right below it there is a string that is exactly the same and is already translated. There are a few hundreds of these duplicates strings.
Removing them one by one through the portal would take loads of time, so I downloaded the table in csv form, removing them manually (still took loads of time), and then reuploaded the csv file with duplicates removed. I made sure to also turn off automatic text capture. I thought that was the end of the problem.
A few days later, my Arabic translations went down to 50%+ translated again. The duplicates are back.
To reproduce this, I suppose you can just delete a bunch of duplicate strings, and then observe that they will come back after some time.
Note that you can find these duplicate strings in all other languages, but because Arabic doesn’t have automatic translation, the problem is a lot more obvious, because you can see the translation percentage go down.