Same issue. 2416 items exported, but only 1713 were imported. In one case, of 3 bank accounts listed under "Bank Accounts" in 1P (all from the same bank...!), only 2 appeared under "Finance". The missing bank account was indeed listed in the data.1pif file.
I have tried exporting from both 1Password 6 and from 1Password 7 to the .1pif format. Obtained the same results.
I tried exporting from 1P6 and 1P7 to .csv (selecting export all fields and checking the "Include column labels" option). In both cases Enpass fails to import anything at all.
FYI there were no items in either of the 1Password trashes as I had emptied them prior to the export.
Obviously with 703 passwords/accounts missing, there's no way I can migrate to Enpass as much as I'd want to since I'm hating 1P right now.
I'm using Enpass 6.1.1 build 408 on Mojave 10.14.6