I got the strace.log but I must admit it’s too much information and I’m not sure what to look for (“languagetool” occurs 19,000 times or so). You might also go to ~/.config/libreoffice, search for any log.txt files there and see if they have useful information. In the end, this is a dialog from LO and not from LT, so the bug/problem will probably be in LO.