OLC-Posting flights ending after 2400UT

Last year I had problems with flights completed on the west coast after
2400UT when another flight was also submitted for the next day.

In my situation I had a great (for me) competition flight which ended
after 2400UT which was submitted and accepted. Then the next day I
attempted to post another flight which by UT started on the same day as
the previous flight ended. Not only was the second flight rejected but
the first flight was removed!

I have not attempted to resolve this issue, at the time I was too busy
flying and just said: #@#@ OLC.

Has anyone else had this problem? How do you get around it? Bound to
happen to me again this year.