I have assumed its deletion from the ASX200 with some short covering first. But I am probably wrong.

S&P/ASX 200 Announcements

The S&P/ASX 200 is regularly rebalanced to ensure a highly liquid and tradable index is maintained.

Two benchmarks are used to compare ASX listed companies and determine eligible for inclusion in the index.
1. Average market capitalisation over the preceding six-month period
2. Liquidity

NOTE: A security is only considered for inclusion when another security is removed.

Quarterly Rebalances
• Occur on the third Friday of March, June, September and December.

Intra-Quarter Deletions
• Occur at any time depending on the situation (e.g. merger).
• Two to five business days notice is generally given.

September 2021 - Notice of Quarterly Rebalances

The first Friday of March, June, September and December.

IE it wont be a rebalance because it isnt the 3rd Friday of March.
Intra-quater deletions occur at any time
I then assume notice will be given tomorrow (2-5 business days notice)

Again could be wrong..