Effects all versions, seed data specific.
This was brought to my attention by a cataloger using some of the advanced search options. When limiting audience to adolescents large print serials are returned in the results. Looking into this, this is because config.marc21_ff_pos_map defines a position for Audn in SER records. Serial records don't have an audience code, that position (008/22) is the Orig code, for original format (and the code for adolescent audiences is the same as the format code for large print).
I'm no cataloger, so while I can fix this particular issue locally, the other fixed field definitions need to be checked so any necessary changes can be made all at once. (Especially because I'm assuming that a reingest is required to completely correct the issue.)
Another example of this problem is that the literary form fields used for books are not used for other item types, like audiobooks. So whenever you do an audiobook search limited to a particular literary form, you will retrieve zero results.