Odd entries in event log

One of our AP-s froze and we had to reboot it to restore connection.

After reboot we noticed odd entries in the event log.

Would anyone know what these entries correspond to.

Firmware we use is 13.4

01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 1 caller 0x8006720
01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 2 caller 0x91ed8
01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 1 caller 0x8006720
01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 1 caller 0x8006720
01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 1 caller 0x8006720
01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 1 caller 0x8006720
01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 1 caller 0x8006720
01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 1 caller 0x8006720
01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 1 caller 0x8006720
01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 1 caller 0x8006720
01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 1 caller 0x8006720
01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 1 caller 0x8006720
01/31/2016 : 10:46:40 UTC : :ev_send() OSFlagPost() failed 1 posting tid 28 (28) evflags 1 caller 0x8006720

Thanks.