Here's what I found...
The 1 month lag between AMC and ETC has been in effect since January 18 2024.
Purple : is the previous tracking from ETC in Dec 18 2023 to Jan 7 2024.
Cyan : is the current tracking from ETC in Jan 8 2024 to Jan 13 2024.
Blue : is the next sequence tracking from ETC in Jan 14 2024 to Feb 11 2024.
Yellow : is my ETC projection from ETC in 2021.