Hi there,
FWIW , li_dayu was who we reached out to … So I dunno what mistake you mean. the solution was provided via seeed. I’m sure you do understand this is emerging tech and when you’re on the bleeding edge there will be cuts. 
You asked how long it was NOT working for. I don’t see the relevance unless you’re making a case but I’m pretty sure since the previous beta release, there is a demo of it working at the show when it came out with 4 cameras. (may have had an additional board though) ? YMMV
Glad you got it working for sure and also brought it to the forum for others to follow along. I would disagree on any massive shadow on Seeed They do a WAY better job at documentation than others, Now Nvidia has a Higher Bar Granted this isn’t that. IMHO 
I’m glad you don’t judge the people, thay are all trying hard to provide a good level of support. I don’t think they rely on customers helping each other as the only means of support either. being around here a while you see between time difference , language and culture differences and many, many products they have it’s a good day when one works. 
thank you for your patients and contribution to the forum.
GL 
PJ