today tested again, but now with a 64bit-container ... no problem at all (of course exactly same version, config and environment) so either the problem may be a compiler-problem or maybe a cut-off value in code due to bad casting... unfortunately the code-base is too large for us to go deeper into it, but it would be nice, if it can be solved, before debian buster with its working version of i386-samba won't be supported any more
