version 8.4 2018-07-26 (build 84192014) behaves the same (crashes on the third import) as 8.5 2019-07-15 (build 85320313). Interesting is the fact that TB.TXT import also counts, I mean if I create a new DB by importing TB.TXT in single user mode, then crash happens after second run of my import (because the first import was TB.TXT)