With all these elaborate but interesting speculations about why Landr rejected a BIAB song I am surprised no one mentioned the obvious (and likely) reason for rejection.
BIAB produces identical riffs for users of the product! And these riffs alone, if detected by software, would be sufficient to get you a rejection.
That sounds as good a reason as any for LANDR to identify content as 'insufficiently distinct', but let me reiterate that they did not actually reject any of my previous eight releases. They merely marked some of them as not approved for YouTube monetization, and then they instantly reversed this decision after I requested more precise information on what constituted 'insufficiently distinct'.
Although LANDR have put my ninth and latest release on hold, their email clearly states that this is only until I provide confirmation that I have full permission to use the third party content that they have detected in my song. (ie. the BIAB Realtracks). Thay say that this is to avoid any problems AFTER it has been released.
Something else has just occurred to me which could explain how their detection system works.
I've noticed that they advertise copyright free sample packages for sale on their website. Mainly for use in house/trap/hip hop music.
It makes me wonder if their AI monitoring system is automatically programmed to allow these samples, but not other third party content, such as BIAB Realtracks ?
Of course there are alternative distribution services to LANDR that are available, but it seems likely to me that they all probably use a similar type of AI monitoring system for flagging up third party content that may require the permission of the owner.
It's all speculation I know, and anyone's guess is as good as yours, mine or Charlie's, but I'm eagerly waiting to see what they do when they receive my reply to their email.
In any event, I'm sure that there'll be a few sighs of relief from other BIAB users when/if LANDR accepts my confirmation that I have full permission from PG Music to use BIAB Realtracks, and they allow my latest release to go ahead.