Experienced twice over weekends when the bbm service could not restart and the notification icon disappeared, messages not received until manually restarted. It lasted the entire weekends on nexus4 running kitkat 4.4 while the Samsung S2 running 4.1 was fine. suspect it was a server/kitkat compatibility issue. Bbm's service is a ram hog growing from under 20mb to over 100mb and budget devices with 512mb may lag and freeze. The S2 with about 700mb seems ok considering the device is laggy as it is. The problem has not recurred since the 2 consecutive weekends after updating the device to 4.4.2 so it's anybody's guess what caused it? Now its running well on both my phones.