DB102738 is the new DB version of Speaker of Mandarin, an Inspector Wexford mystery. It may already be in your catalog in other formats, and if those have the same Series heading as the DB format but no title links between the records, your patrons' Series preference can get "stuck" on the title.
Other formats:
RD 19834
RC 19834
BR 05584
Please check your catalog for other versions of Speaker of Mandarin, and if present, add an "AltFmt" title link.
Let us know if you need assistance or have questions.
Am I missing something, or wouldn't the patron have to be active in these formats for this to be an issue? That patron would be a rare bird, indeed, at this point to be active in all four media.
You're right that I simplified this slightly. The patron doesn't need to be active in all formats to trigger this issue, but they would need to have at least one of the others listed on their Series preference.
So long as the Media field of the preference only contains DB, you're all set--but patrons who had the preference added while they were also still Active in cassette may have C,DB listed. This causes KLAS to say "oh, they haven't had RC 19834 via series yet, that's seq num 12. Let's send them #12." But it can't send them #12 in RC because you no longer have copies and the patron isn't active in RC anymore anyways, so it sends #12 in DB... but this doesn't mark RC 19834 as HasHad, and thus the process repeats.
An alternate solution would be to ensure that the Series information is removed from any RC titles still in your catalog, and/or to ensure that all Series preferences are only for DB. However, neither of those addresses the Braille version. Especially once you are circulating e-Braille for the NLS refreshable braille devices, it will be perfectly valid for a patron to be active in both BR and DB. Those patrons will likely prefer to get a Series in one medium or the other, rather than both... but that can be easy to miss when adding the preference, and there may be some patrons that really don't mind getting a mix.
Adding the title link will ensure that they don't get caught in a loop and only receive that seq number once. So while it's not the only solution, we do recommend it, especially for the BR format. And if you don't want to add the link for some reason, make sure that one of the other solutions (removing the series info from inactive formats and/or removing inactive formats from series preferences) is in place.