Thanks for the recommendation. Tusky is the app I am using primarily (I typed the wrong name above, sorry.)
However, once I finish redacting a post and want to then add another toot link, I need another app (FediLab.) And then, the problem occurs.
FediLab has quite a few more worthwhile features (e.g. being able to read the thread that you are responding to while redacting,) but it has always been highly unstable on my phone, which has an OS update about...