Could anybody please repro with X3E?
 
STEPS
 
1) New project
2) Add a Dimension Pro soft synth track + patch.
3) Route your keyboard to correct MIDI in channel for track.
5) Arm record the track.
6) Set loop to be around 4 bars.
7) Click and hold record button and tick sound on sound
8) Press record.
9) Make sure you play a single note every time you hear the metronome.
10) Continue loop record for 1 minute.

EXPECTED
You are able to hear other notes as you loop.
 
ACTUAL
Eventually the MIDI note gets stuck.
 
Many thanks..
 

I've just followed the steps using SI-Electric Piano (I have Dim Pro but it's not installed) and the loop recording works beautifully here, even with input quantize enabled.
(And it successfully created 7-8 take lanes although I much prefer to record everything in a single lane, with the clips being automatically merged... )

Just to double check, with sound on sound recording mode?
Thanks Jlien

Yes.

Thanks for that Jlien. OK better check out my system (buffers etc).

Check drivers, BIOS, yada yada
... Rescan VSTs.... :D

Almost correct!
Under Focusrite Mix Control 3.4 I had to clear all the settings and restore the factory defaults.
Then all was well :)

Cheers ;)

Hmmm... I should check this one myself then. I just installed the MixControl 3.4.
 
Edit: Just ran a check of this and was not able to reproduce with MixControl 3.4 installed. 14 additional takes of looping sound on sound (single note to the metronome) after the initial track recorded.