Bug Report #2: Vanishing Lyrics, Version 2.1.0 rev 871c8ce

When copying a single note you need to be careful. If you click only the note head, only the note is cut. Since there is now no chord there, the lyrics are lost. Use Shift+click to select the entire chord which includes things such as the lyric, accents and so forth. You will know you have the entire chord selected because the stem, lyrics and everything attached to them will turn blue.

I've done this often enough to say that this does work, if it is a range selection. Selecting a notehead though probably doesn't do this, the lyrics is attached to the chord (noteheads, stem, flags)

Again, not sure why you think should be the case (or which previous posters you're referring to).
If you copy a single notehead (single click the notehead, no rectangle around it), then again select a single notehead upon pasting, then only some notehead properties are transferred; such as the pitch and the notehead group (cross/diamond/normal). It will leave articulations and lyrics intact

As soon as your selection shows as a rectangle, it is a range selection and consists of at least one full chord (even if it has only a single note in it) including all lyrics/articulations from it. Pasting that range will overwrite whatever was at the source.

Your two questions seem to indicate that you have different expectations about how musescore is supposed to work and how it does work.

Consider taking the time to watch at least the Note Input tutorial found at https://musescore.org/en/tutorials
See also https://musescore.org/en/handbook/copy-and-paste for specific information on copy and paste within MuseScore