IMUGENE CHART. TA only, page-18438

Yes I saw this one too! The Condition is S3XT which I believe is a Block Special Crossing or Cross Trade. I note it's not visible in my 1-min, 5-min, 15-min, 30-min or hourly Volume charts at 12:00:08!

Commsec says 'a cross trade occurs when a broker executes an order to buy and sell the same security at the same time, in which both the buyer and seller are clients of the broker. A cross trade is represented by XT in the course of sales. If your order has been cross traded, your contract note will state this'.
What do CX, CXXT, and NXXT mean? (commsec.com.au)

Investopedia describes Block trades as 'a large, privately negotiated securities transaction¹. Block trades are arranged away from public markets to lessen the effect on the security's price². They are usually carried out by hedge funds and institutional investors via investment banks and other intermediaries, though high-net-worth accredited investors may also be eligible to participate¹.'
Block Trade Definition (investopedia.com)