How to read notes with an "ornate X" notehead for guitar?

Question

I am not sure how to read notes with noteheads that look like a double-sharp (see the image below for an example). So far, I have dicovered that this notehead might be called "ornate X notehead" and can be found in the SMuFL specification.

At first, I thought this might be another style of writing ghost notes (usually with a simple X as notehead). However an arrangement of "Sweet Home Alabama" in one of my songbooks contains such ghost notes with a simple X as notehead while the chorus has these ornate X noteheads. So the latter cannot also stand for ghost notes. By the way, alongside standard notation the songbook contains tabulatur where these noteheads appear too, without a stem of course. So, how do you play these notes on guitar?

Update: Adding examples from the songbook as requested in comments. First image shows the use of use of convential x-noteheads for muted notes in the intro. Second image shows the ornate x noteheads in the chorus.

Answer 1

So this must be dead notes:

I’ve found this description in a german wiki:

A dead note or ghost note on a guitar is a tone that does not have a precisely defined pitch, but is more like a dull clack.

A dead note is generated by not pressing the string down on the fingerboard of the instrument when striking it, but only touching it with the index finger, middle finger or the entire palm of the hand and thereby dampening it. The string is struck in the normal way by plucking, playing the plectrum or slapping the electric bass.

Dead notes are marked with an "x" on the staff or tab and are often e.g. with the electric bass on the line on which the open string would normally stand. However, it is still considered as a counting time.

Source: https://de.wikipedia.org/wiki/Dead-Note

For more information:

https://www.ultimate-guitar.com/en/wiki/Dead_note

A dead note effect is achieved by resting your fretting hand across the strings without actually pressing the strings against the fret. A dead note (also called muted note or silenced note) adds more percussion than pitch.

Answer 2

The 2 eighth notes on beat 1 and 3 are immediately muted as you can see in this video:

When he sings mute mute strum he explains how he holds his right hand on the strings **muting ** them by the hand. These muted notes are your notes with the x-heads.

also this guy explains he is stopping the 2 notes with the plec:

Answer 3

Meanwhile I've bought the book "Behind Bars" by Elaine Gould and found the answer: "The double-sharp sign is sometimes used for crossed noteheads, but is best reserved for use as an accidental symbol."

The book also confirms our assumption, that double-sharp noteheads may indicate "finger damping" amongst other uses, which are not relevant for this case. However, it is a completely confusing inconsistency to use both the crossed noteheads and double-sharp noteheads for the exact same function in one score, like we have seen above. The arranger simply made a mistake.