Cisco Switching/Routing :: C3950 - Intermittent Message / May Suspend At Level 4

For a week now, one of my Cisco 3945 routers displays, from time to time, the following message in its log:
 
2012-07-16T14:12:43.852017+00:00 cb00-r103 220: [syslog@9 s_sn="59"]: Jul 16 16:12:42 MEST: %SYS-2-INTSCHED: 'may_suspend' at level 4  -Process= "OSPF-100 Hello", ipl= 4, pid= 320
2012-07-16T14:12:43.852017+00:00 cb00-r103 221: [syslog@9 s_sn="60"]: -Traceback= 15CB073z 9081B7z 2851571z 11B7582z 11C275Ez 11C2906z 11C03E3z 1B907B5z 1B9064Cz 1BA5737z 172047Fz 47FFDCz 4D2EEDFz 4D2ED71z 4D2EA2Bz 4D30097z
2012-07-16T15:06:11.686817+00:00 cb00-r103 222: [syslog@9 s_sn="61"]: Jul 16 17:06:10 MEST: %SYS-2-INTSCHED: 'may_suspend' at level 4  -Process= "OSPF-100 Hello", ipl= 4, pid= 320
2012-07-16T15:06:11.686817+00:00 cb00-r103 223: [syslog@9 s_sn="62"]: -Traceback= 15CB073z 9081B7z 2851571z 11B7582z 11C275Ez 11C2906z 11C03E3z 1B907B5z 1B9064Cz 1BA5737z 172047Fz 47FFDCz 4D2EEDFz 4D2ED71z 4D2EA2Bz 4D30097z

[code]....
 
It never happened before and the configuration did not change. The only thing that happened, the WAN connection (point-to-point to a Cisco 3845) went down and the router rebooted while the WAN was down. When the WAN came up again, everything went fine, until about an hour later and the first occurrence of this mentioned log.This 3945 does establish an IPSec tunnel with its peer (the 3845) and all the traffic, including OSPF, is going through the tunnel.