Security – 260 – Forbes Signal Article

Forbes put out an article on how Signal has some weaknesses using the after first unlock theory.
TL;DR – Yes, but not limited to signal. Power off your phone if you are worried.

https://www.forbes.com/sites/thomasbrewster/2021/02/08/can-the-fbi-can-hack-into-private-signal-messages-on-a-locked-iphone-evidence-indicates-yes/?sh=27331c526624