Hi @DarrenBravo !
I'd also go with BFD in this case.
Regarding your question
I recently had an issue with these switches in that when I connected a laptop over a different VLAN (ports are trunked and VLAN's are permitted on the ports), DLDP would (somehow) detect a unidirectional connection and would block the port. Once DLDP was disabled on these interfaces, I can connect via that VLAN. I don't understand why!?
Keep in mind that if STP blocked the link between IRF stacks, DLDP also stops working on such blocked link. Try to check the logs on both IRF stacks ('display logbuffer') and search for events that happened just before and after that link loss. Hopefully the log will help to shed a light on what's happened when you connected the laptop.