This is because iTunes can’t read CD-Text. You need to submit a CD’s info to Gracenote database for iTunes to display that info.
So what you see is probably normal, and if you have filled out the CD-Text info correctly, that’s the best you can do. ISRCs are irrelevant here.
More here:
I use one of Doug’s Scripts to quickly transpose CD-Text to CD Info/Metadata in iTunes which can then be submitted to Gracenote.
It turns a tedious task into just a few clicks but due to the nature of how Gracenote works, you only want to do this with the FINAL master because it goes based on the number of tracks, and their respective lengths, and it takes some time to go live in the Gracenote database.