This is a regression.
Hledger 0.23.3 correct sorts the entries by their second date. Hledger 0.26 does incorrectly sorts by the unprinted date1 when passed the --date2. I haven't been able to pin down when between these two versions the behaviour broke.
reg: fix sorting regression with --date2 (#326)
And rewrite/clarify postingsReport.
Thanks for the report! I believe this is fixed.