When a Command Block that is set to "Always Active" gets switched to "Repeat" mode it does not repeatedly execute its command until the "Always Active" status is diabled and re-enabled.
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It has already executed the command for the impulse command block, so it doesn't reactivate itself.

Confirmed for
15w36c I would say that this is valid as this also happens when you place a chain command block and then switch the type
The problem is rather that there is a missing test ifauto
is already true
Confirmed as a bug in 1.9.1-pre3.
There's another ticket open for this.
Shouldn't this one be a duplicate then?
It may be just me but the video file attachment doesn't load correctly when viewed in browser, but when downloaded.