Last screen is only supposed to work when opening from suspended. It doesn’t function when opening from a cold start.
I’ve noticed my phone working less good lately because it’s on its last legs. (Typical apple “its time for you to buy a new phone so yours now sucks”) and I’m pretty sure it’s closing apps in the background when it gets “tough” to run all the apps I have open. Then it seems that it treats every open of APDL as a cold open.
In other words, in my case, I think it’s not APDL’s fault.