I can't check my wallet, but it appears that it's all back to normal.
The double payouts was my mistake, not mpos. I ran the wrong cronjob so the system thought it was OK to run the scheduled payout cronjob that runs every 60 seconds. I noticed the wallet balance on the site was dropping like a rock (because two payout crons were running at the same time, under different process names) so I canceled it quickly however some users will be in the negative as I reversed the transactions. The reversals will appear as a fees in your transaction list.
Normally, the cronjob will not ever run twice at the same time, because it has the same process name, but due to my mistake the payout cron ran twice, as did the round earnings cron. It took a while to fix but it should all be correct now.