pretty sure it goes something like this;
you dispute
cra has 30 days (not unheard of for 45 days for dispute from your annual freebie) from receipt to investigate (ask furnisher to verify).
if the ca/furnisher verifies it stays
if the ca/furnsiher updates new info is noted and fico adjusted
if the ca/furnisher fails to respond, update or validate entry comes off and fico adjusted.