Expression changing values

I am concatenating data into Gcode commands, based on an example I found.
I need to create strings with the values from a series of sources, in this case: X Y Z, and E. The values for x y and z are inserted in the string correctly but E comes out messed up, although before going into the expression it looks fine.
Any ideas?

Thanks (17.0 KB)

I just found out that changing the “E” for Z or A, for example, works! Is E a reserved letter for some reason?

Of course it is Eulers number… For future desperate people, just use ‘E’ and you’ll be fine