MPC 3.0 recording hardware question

I am very new to MPC. I have a MPC X SE.

I am having an issue understanding the recording audio tracks.

I have a bass line on a midi track.
I am sending that to a hardware synth and patched back to the Mpc.

The sequence is 16 bars.
The midi track was an 8 bar loop (bass line)
When I try to record the audio back from the synth it cut of at 8 bars and because I was monitoring it I get silence.
When I hit play it loops the 8 bars.

All of this is fine, just not what I was expecting.

So I dig in to try to understand how everything works.

I double the bass midi loop and tried to record again.
In arranger view I can see that the midi loop did double and is playing through.

But....

the same thing happened when re-recording audio... it went silent after 8 bars.

So on the sequence I turned off the loop button and it worked... but as previously mentioned I had already made the midi 16 bars to match sequence. So I would have expected to record a full 16 bars. The length on the audio was set to seq length.

I do have other midi tracks that are 8 bars, 1/2 the sequence.

I suspect if any midi track loops on a sequence that the recording stops.

Can anyone clarify this for me. I would like to fully understand how things work.

Thanks!

g