DBI config storage does not use transactions
LL::NG::Common::Conf::DBI, CDBI and RDBI handle are set with AutoCommit = 1 (however, in those packages, 'store' tries to do a commit).
There is no problem with DBI and CDBI, since storing a new conf is done in one single INSERT request. But it does in RDBI, since storing a new conf requires around 150 requests and can last around 1 second : if LL::NG portal or handler is run in that time, it loads the new config, and that config is incomplete, so it fails.
The bugfix is really simple : just set AutoCommit = 0.