Keyboard Shortcuts "Shift+Left/Right/Up/Down" Does Not Move Cursor and Select Text in Messages App

After updating my 2016 MacBook Pro (TouchBar) to BigSur, I noticed the following software glitch when using Messages App:

After having typed a text in the text field, the keyboard shortcut Shift+Direction Arrows (up, down, left, right) which normally would move the cursor and highlight the portion of selected text is no longer working. It works on every other software and app, just not in Messages.