Yes ok alignment matters.  LMDB data is just a sequence of bytes so it is not doing any alignment, and I presume each LMDB value starts aligned.  I'm using speedy for most of the data, and I see zero issues on the speedy repository about anybody getting alignment errors.  That is why I'd love to see an error message, so I can know this issue is real and then chase it down, rather than trying to fix something that might not be broken.