Converting pdf with thai text to pdf+text with OCR fails

I tried to convert a pdf document with thai text with OCR to pdf+text.
After conversion the thai text can be copied, but after pasting gives text in an unknown font.
What can be wrong?

The OCR does not support Thai, unfortunately the Thai option was enabled by mistake .

I am not happy with that.
A workaround?

Sorry but there is no workaround besides using another OCR application that supports the Thai language.

If you’re comfortable (somewhat) using the shell, you might want to take a look at OCRmyPDF which uses tesseract that has support for thai.