Thanks. I'm surprised it needs a commandline option, given that SegWit is off by default.
SegWit is off by default. Activation is detected by the node it is running against. Therefor an offline instance cannot detect SegWit activation, which is why you need to manually enable it.
Has Armory got slower to launch recently? I had it running and synced, closed it, then immediately restarted it. It's taken several minutes to build databases and now says an hour to scan transaction history. I'm sure it used to be much quicker just a few months ago.
Some event increased the address chain without registering the new addresses. On the next run, they have to be scanned.