problem with tunnel monitoring

[sxpert]

Good evening
I have vtun and gre tunnels I want to monitor but hit the following issue :
at first, the monitoring works perfectly. when the tunnel restarts after a connexion failure or something, cacti is apparently not able to grab info from the virtual interface

one thing I have notice is the ifIndex appears to change.
using ifName or ifDescr as Index Type in the data source doesn't seem to help...

[BSOD2600]

Since the index number is constantly changing, I'd suggest changing the reindex method for that devices query.