I found a very interesting bug, from prehistory :-) Nobody complained, but it is a nasty bug.
I am talking as reference to official 5.17.0:
generate.cpp, line 2153, tmp_minWrong may remain INF, if there are no conflicting activities. So a very good position is rejected!!!
Thanks to yush for the persistence in finding this bug!
I really thought everything was perfect, but you can never be sure :-)
Will be fixed in the future 5.18.0 and in the future snapshot.
The bad news is that the random seeds after generation will change. And I have to recheck all my input files, some of which take hours :-(