I recognise the error, there is a B-F between the octaves and the top voice, which is a fifth.
There is also an octave between voices in the second bar.
So, I get the essence of what you say- the octaves may be terminal but not between 2 independent voices, am I right? Thank you for replying by the way.
But is it fine if fifths or octaves between two voices are repeated
Is it a parallel fifth if I repeat the same fifth? No, parallel fifth occur only with different perfect fifths. The same perfect fifth (or perfect octave) repeated is not considered a parallel because no change in harmony occurs.