I am the idiot, I know at least 2 other photographers who returned there Leaf Aptus 75 backs because of the same problem and purchased Phase. Its not just me, but a bad Leaf business model.
about the issues:
i know several collegues who have not full working backs, but the promise to get some "selected" backs and so they wait and wait and wait. some others have got in the meantime 3 or 4(!) backs ,- i talked also with photographers who dont want to post about their faulty backs because they hope on "betterwill" from leaf if they dont speak bad in public.
as from the beginning most affected are still shooters with shift cameras/ lenses. centerfold with normal mf lenses seems to be controllable mostly with the gain adjusting, but i dont know so many photographers who work outside architecture so my infos are about this special aerea, as allways. and for architecture one use normally shift lenses, where this issue may appear stronger or at least it affords for every new setting a new white gain file, meanwhile mostly with normal mf lenses one white reference can do a pretty good job ( at least in brumbaer tools with sinar, i suppose with gain adjuster it should be similar ).
i.m.o. sinar was rescued through stefan from a similar desaster-,- although its allways hard to say what would have happened if the things would have gone a different way,- so maybe someone there would have found finally a similar code as stefan did, who knows. i really would like to know if dalsa has learned its lesson and will bring out better sensors in the future. if not,- it will look dark for them in mf photography. this would be a pity, because i.m.o. its still the better sensor ( for lo- iso work ).
all this is a crazy story and it seems as there will follow soon a big bang ... if my infos are right. but i will not post more about because i dont want to be the first to publish heavy rumors. lets see.
about the prices:
its very astonishing that there appears such a huge difference between sinar and leaf. seems to be also crazy,- lets see if they will correct this but i think it should not take too long time for that, if leaf wants to sell some AFI/HY cameras too .....
the changing adapter plates on the sinar backs are more worth than its weight in gold, as it seems. i used them a lot in the past,- cause i changed several times my system till i found "my" mf system. changed form my old hassies to contax ( what a relief .... ) and also the gottschalt,- in opposite to alpa- has its own mount, at least in case of my rotatable back. so i changed the adapter from hassy to contax,- this was all i had to do and so i use still my "old" first e75 back, which is now updated to a 75lv.. i unmount the back between the contax and the gottschalt which works pretty fast. also i worked several times with the sinar m for aerials, doing the same here,- changing the adapter. so in total i worked with this back with 4 different cameras, each afforded another mount.