A =3D wasn't properly encoded (should be kept): APE=MAN MAN=APE
A =3D wasn't properly encoded (lowercase): ape=man man=ape
Lowercase hexchars: =bb=a1=4b=44=45 =72=75=6c=65=7a=21=ab
Mixed-case hexchars: =Bb=A1=4B=44=45 =72=75=6C=65=7A=21=aB
A misplaced (unencoded =3D), followed by whitespace: =  not at end!
Two consecutive =3D at the end of the line: ==
A misplaced (unencoded =3D), as the ultimate character: =