Hi,
Thank you for the details, it helped a lot!
I needed to make a few debug changes to the plugin code to resolve this. Looks like the “pll_register_string” function was not working correctly from the polylang API, there was probably a change of some sort that I am not aware of.
It is not perfect, but the strings should appear now. For each search instance there should be separate strings now – the search ID is in a parenthesis (where applies).
I will have to debug this issue on our local servers to see what exactly is going on, and apply a fix to a later release.