Module voicemail reload causes interrupt

I am using asterisk version for IMAP voicemail in which I have about 50 users. Whenever I reload app_voicemail, Asterisk voicemail is dead air and the console freezes. After a few minutes the module seemingly finishes reloading and voicemail works. Is it normal that voicemail should not work while the module is reloading? Can this be related to IMAP as I assume others don’t have this issue with non IMAP voicemail or else we would hear about it.