There are a number of threads that deal with external storages for car stereos where some of these devices seem to have problems with any actual metadata so the order from the FAT is taken.
See e.g. here:
So it could be necessary to sort the directory first.
Alternatively, it may be ncessary to delete the old files first and write the new names to get them into the correct order.
But all these are problems that can only be solved locally by trial and error.