I started with the current master of the code here:
https://github.com/mambax7/oledrion.git
I did a quick scan of the code to see this:
$ grep -r pcntl *
class/Gateways/Paypal/PaypalGateway.php: $pid = pcntl_fork();
The takeaway from this is that there is only one 'pcntl' call in the code, and that is a fork. Nothing is waiting or watching for another fork, i.e. a pcntl_wait() call.
The botched mysqli connection is due to the fact that the process was forked, and the first fork that exits closes the database connection, leaving all other forks with a dead database object.
I am not sure how things ended up in this state. It is possible that the mysql and mysqli extensions behave differently in this circumstance. It is also possible something important is just missing.
It will take more research to get a handle on this and determine a plan of action. But, this is not a stupid problem. It is a very interesting problem.