pptp_local and pptp_remote are arrays
pptp_local and pptp_remote are arrays

I believe these should reference the [0] array element of pptp_local and pptp_remote. The code in interfaces.php only presents the [0] (first) array element to the user for editing.
The current code also does not preserve any additional pptp_local, pptp_subnet or pptp_remote entries in the coma-separated list in the config. That is redmine bug #4568.
I am currently integrating the fix for Redmine #4568 Preserve MLPPP settings when saving interface settings. The fix for that bug will add more code to preserve additional pptp_local, pptp_subnet or pptp_remote entries.
For now it would be good to have this little fix to the existing code - then the fix for redmine bug #4568 will sit nicely on top of it.
BlackstarGroup/pfsense,ch1c4um/pfsense,pfsense/pfsense,pfsense/pfsense,ptorsten/pfsense,jxmx/pfsense,brunostein/pfsense,ch1c4um/pfsense,NOYB/pfsense,jxmx/pfsense,NewEraCracker/pfsense,ch1c4um/pfsense,phil-davis/pfsense,phil-davis/pfsense,dennypage/pfsense,brunostein/pfsense,NOYB/pfsense,dennypage/pfsense,pfsense/pfsense,dennypage/pfsense,BlackstarGroup/pfsense,dennypage/pfsense,NewEraCracker/pfsense,BlackstarGroup/pfsense,phil-davis/pfsense,pfsense/pfsense,jxmx/pfsense,ch1c4um/pfsense,NewEraCracker/pfsense,NOYB/pfsense,ptorsten/pfsense,NewEraCracker/pfsense,phil-davis/pfsense,ptorsten/pfsense,brunostein/pfsense,BlackstarGroup/pfsense