Thanks @justsumguy. I thought the same. Just got off a call from...

Thanks @justsumguy. I thought the same. Just got off a call from Commsec. Apparently there was a tech glitch on Friday and Monday.

All trades (as I was advised) weren't offset, which meant that instead of settling the difference the entire amounts are being settled.
As such, they want me to call them up once I receive the settlement rejection SMS tomorrow, so they can waive any fees and rerun the direct debits.

Cheers!