Future Tense with Middle-Passive Endings

I’m working with Schoder’s book and there’s something I don’t understand.

There are some active (not deponent) verbs that have active endings in the present stem.

Then in the future stem, they suddenly have Middle-Passive endings. Do this mean that in the future they still have active meaning?

If so, my question then is how, for those verbs, is the Future Middle-Passive expressed?

Thanks for any help…

Indeed, any verb that has a “active” ending in the present and “middle-passive” in the future
retains its active meaning.

See Smyth 805 ff.