Don't use a ROM manager, they are buggy and cause issues. - For future reference to get out of a bootloop just hold volume and power and it'll boot you into either download mode or Recovery mode (depending if you choose Vol UP or DN)
If you got the bootloop by just installing the Custom recovery, reboot the device by taking the battery out and placing it back in and powering up. If that doesn't work, reflash your recovery again and you should be good to go.
As for the recovery is not seandroid enforcing
set warranty bit : recovery
That is normal behaviour on a Samsung device when you use a custom recovery and nothing to worry about.
// LG G3 (D855) // Stock // Stock //
// HTC One (M8) // GPE Stock // Stock GPE//
// Nexus 7 (flo) // Android L // Stock//
S3(White) > M7(Red) > Note 3(Black) > Nexus 5(Black) > M8(Gunmetal)/LG G3 (Titan Grey)