I think I have, I managed to replicate your issue when I increased the max image size on the Artwork tab from 1000 to 5000, an image of the composer Camille Saint-Saëns caused your file to be unreadable, the image was 4664 x 4664 pixels in size but more importantly 19,104,574 bytes in size (i.e 19mb)
It seems the limit for an image is about 16 mb - https://hydrogenaud.io/index.php?topic=60122.0 confusingly in Flac a METADATA_BLOCK_PICTURE block has a 32bit field to store the length of the data (i.e about 2GB), but its METADATA_BLOCK_HEADER total data length field is only 24bit, and this limits max size to 16,777, 215 bytes.
I started with original file again and set max image size to 4000 and that reduced the image size to just 3,133,177 bytes and then the file was readable okay.
So now need to devise a fix to prevent images larger than the limit being set, the tricky thing is you cannot just say create an image less than 16.7 mb. You can only say create image less than x by y pixels and see by trial and error if small enough, alternatively keep image size but modify compression settings.