Case system questions

[conlang-creature]

While attempting to develop a basic case system using prefixes I discovered something unusual. The word affects the prefix through harmony systems, but the prefix in turn affects the word through sound changes. Is this naturalistic?

I don't have my document available but here's some examples that have the basic idea:
To +
-Kena
-Bilo
-Mere
-Jun

Leads to:
-Tukna
-Dobilo
-Tumere
-Tuin

[Creyeditor]

Yes, the general idea sounds naturalistic. Why shouldn't it be?
It would help if you could give details on your harmony (vowel harmony, I guess) and the other sound changes. I could try to guess from the examples, but it would be easier if you could explain it.

[conlang-creature]

Ok, the idea seems weird for some reason. I'll give specifics when I have the chance.

[thethief3]

Generally cases aren't prefixed and prefixing languages usually lack case systems just something to note.

[Visions1]

Aramaic does prefix cases though.

Yahɔv Leh Rə'uven LəShim`on Bəkaspi
He-Gave to-him, Reuben OBJECT-Simon OBLIQUE-money
Reuben gave Simon money.

I.e. Lə and Bə for Object (normally accusative, but sometimes dative; can be genitive) and Oblique (in, on, at, alongside, by means of (this latter sense can produce dative)).