zmupdate -f simply reads info from the dB and turns around and writes it right back to the dB.  It looks like user Stan added this back in 2011, but I don't know what his intent was. This same command was also part of the stock zm init script, but after discussing it with mastertheknife I commented it out (the one in the init file).  

TLDR: This might be the cause of the Conig table corruption issue.