The keyboard shortcut "Ctrl+." (for Go to Next Marker) displays an underlined "e" character at the cursor on text files (such as .php, .js, or .html). The menu item "Search/Go to Next Marker" works properly, and both the "Search/Go to Previous Marker" menu item and its shortcut "Ctrl+," also work properly. It's only the one keyboard shortcut that fails.
From Help/About: geany 1.38 ("Sulamar") - Using GTK+ v3.24.33 and GLib v2.72.1 runtime libraries From terminal, geany -V reports: geany 1.38 (built on 2021-10-14 with GTK 3.24.30, GLib 2.68.4) Running on XUbuntu 22.04.1 (LTS)