Text shows strange characters after saving a file

[Felix-Bolivar27289475jl1h]

Why is it that frequentely now (it was not the case before), I get strange charcaters in a text when I save the file. For instance, I type "This is to certify that", and this is what I get when I save the file (see below too):

₂ 0 ⁸ 0 35414⁸ ⁶ 2 6 0

Any help/tip is highly appreciated