It's a side effect of the system PPRuNe has introduced to combat the problem of spammers registering to post their ads.
Newly registered members' posts have to be approved by a Mod or Admin before they appear on the forums. When they don't see their post appear, they sometimes assume something's gone wrong and try again.
When they are approved as a genuine user, sometimes all their attempts appear.
Heliport
(I've removed the duplicates.)