That is correct, unless an offset is applied. A certain encoding system allowed for this a long time ago, and exhibited a similar behaviour to what you have observed, but it was decrypted. This is a stronger version of it.
I have also noticed, certain letters in certain places don't appear to encode, but that's because they're mapped to themselves. With this system, it is bound to happen sometimes, even with an offset.
IPH E4rFkj 98yX qOuT Iz5t i5 4VbrHaQ, G7n8y TjX3 SLfF If yhbNZzTOEo89 6MU8D3fZ77. U SE2Kf HjTuFL dFi 6MU8D3fZ7 C0IiO 3c 5msBap x5 v Yho2 Ts9 K Oxjw waDMws 5pCpkfc q1 GIbmx4I r9OJKu8QVGl, sKq CJAUvM dK5XC I2 r pI5oCl1 zc qub Pz 9hWJ H6L 3DLA N5 17jq I1A0u 6aV VTY HonoSBN ID ZBSvaJCxd BI n g6hT uLC2, lK CA rWCa OM3Z zpr4J7 z odZ3Ei BUbrX
