We already have logged table-layout:fixed related issue as PDFNET-42356 in our issue tracking system. I have associated the issue ID with this thread as well, so that you will be updated once the issue is resolved. We will certainly share updates with you as soon as we do some significant progress in this regard. Please be patient and spare us a little time.
Can you please confirm if you are using 22.3 version of the API? Also, please share your sample HTML file in .zip format with us. We will test the scenario with the latest version of the API and address it accordingly.