Hi Mei,
Thanks for the info. I replicated in 2712, then tried it in 2715 - success! TL-8247 fixes the issue, an upgrade to 2715 will resolve (this was the related issue I mentioned earlier).
" TL-8247 Fixed missing history records when not overriding the current record during a course completion import
Previously if you ticked the override checkbox when uploading course
completions, but the most recent completion date in the upload was less
than the current completion date in an existing record, the upload would
ignore the first record and move straight on to the next one. That first
record is now placed into history instead."
cheers,
George.