There is a 500 blueprint limit for adding the .blueprint_data field.
Your 2 characters that show it, are under that limit, but when it processes the 3rd one it skips it due to the count being over 500.
You can either request a certain page via the parameters (character_id, search_string, strict_search, page) that would return you a 500 blueprint page.
Or just call the .Blueprint function seperately with the .type_id returned from the “light” variant omitting the blueprint data.
But I do see this logic fails when you search a list larger than 500, since if the results are under 500 it should include the blueprint_data, that specific issue should be fixed in the next patch, but the 500+ limit will remain as this function can crash the addin, even in desktop, if blueprint data is included on characters with a lot of blueprints.