Ah, the joys of music convention. I went through all seven volumes of the Mel Bay methods books and the later volumes had lessons on some obscure chords. I ran into lessons where the “rules” require the notes be written as E# or B# on some keys. And Guitar Pro is an absolute stickler at following rules.
Explained better than I can at this link:
https://www.sarazhandpans.com/handpa...at-and-f-flat/
With highlights pasted below for those who are link adverse.
SO WHY WOULD ONE WRITE IT AS AN E#?
When properly writing scales, the same letter is never used twice. For example, in the scale of C# Mixolydian, the scale is properly written with an E# and F#. For this reason, the “F” note is known as E#. The same is true in F# Major and F# Harmonic Minor, which both have a major 7th scale degree, known as E#. You can read more about it here.
Aside from the previously mentioned scales, we have also released a C# Major scale with a B# and E# as well as explored an Eb Minor scale with a Cb note. 😉