On both a Pixel 7a running Android 16 and a Tab S2 running Android 7 (I know, long in the tooth), I can select text but the text between the ‘handles’ does not get ‘marked’. This makes it difficult to tell whether I have selected the right text, especially when I am selecting multiple lines. I reverted the K-9 app to v16.1 on the Tab S2 and the problem disappeared.