Weird bug? Exit delay started when set at 0s (home mode)

Hello. Tonight using my keypad, I put my alarm system in to “home” mode like I have done every night for the last 3-4 years. Only tonight something weird happened….About 10 seconds after the system successfully entered home mode I heard the ‘Entry/exit delay music’ and audio message “exit delay started”. The problem is: for me in home mode my exit delay is set at 0s. i.e. the alarm activates immediately. I have verified everything above through history; the mode I entered, what subsequently happened, and checked the mode settings to confirm exit delay was set at 0s. This is the first time in 3-4 years of using the alarm system that something has “gone wrong” and my confidence in it has dropped. Is there a known bug or something I’ve possibly overlooked here?Thanks.