I use EAC + FLACCL to rip to FLAC, using the most extreme compression.
Afterwards, I typically use MP3TAG to alter/update the FLAC tags.
Now I have happy, high quality lossless copies.
For more space-constrained listening devices, I use dbPowerAmp (v16.6) to convert to MP4 at maximum quality VBR. As part of its conversion process, it copies the FLAC tag contents over into new MP4 tags. It does not copy the FLAC tag itself into the MP4 file. However, it creates a couple extra items in the MP4 tag for the encoding tool & iTunes support. I dislike these superfluous items and have always used MP3TAG to remove them.
Here is where MP3TAG has recently begun showing a bug: A few days ago I upgraded from version 2.87 to 2.94, and then used it to removed a couple unnecessary items from a folder with 11 MP4's that had been 69 megabytes total, and MP3TAG inflated that folder to 13.1 gigabytes! I've since tried several other MP4's (all created with dbPowerAmp), with the similar results.
Please let me know where I can upload a sample, and possibly my MP3TAG configuration.
Thanks in advance, and thanks for the (otherwise) excellent and free tag editor that I have been using these many years.