Hey there!
We’re using the exact same drone for thermal inspection of solar power plants. Converting the images to .tiff seems to work fine for you, nice! I found that after you converted the images to tiff you absolutely have to copy the original exif-file-tags to the tiff-images, otherwise strange things will happen in ODM.
The command I’ve been using in scripts for that is:
exiftool -overwrite_original -tagsfromfile ./pre/%f.JPG -all:all ./post/
This takes the tags from the files in the local “pre” folder and copies them onto the files in the “post” folder. You can check the tags with exiftool ‘path/to/image/imagename.tiff’.
Also see the topic I opened here in the forums. 
Still haven’t managed to, but planning to create some proper camera calibration values for the distortion using OpenCV. https://community.opendronemap.org/t/lens-calibration-of-thermal-camera-dji-3t
Welcome to the forum!
Cheers