It's how AWM has worked for generations including this one. FM-X will be smooth. So not inherent to Montage. Just one of the two engines. There are several past threads covering this in one way or another including links to historical requests during Motif XS and other generations asking for this to be "improved".

FMX also is not smooth. I think the Problem is in the management of rnp0 pitch bend message, at the roots of montage core programs. I am sure it could be resolved by an update but it sounds like to not have a smooth linear portamento with an external controller does not concern a lot of customer I suppose.

Perhaps - not sure exactly what MPE does. If you turn portamento on and run your hands up and down the keyboard - FM-X will glide smoothly due to no retriggers of the attack while AWM2 will not, in general, be smooth due to each new note retriggering the attack portion of the waveform. Even if you clear one hurdle - I believe the waveform handling will still get in the way for AWM2.

there is a post about my issue

" Montage/MODX Pitch Bend micro Stepping-like Sound - Not 'Smooth'
Please fix the Pitch Bend functionality on the Montage/MODX to be more 'smooth' like it is on previous synthesizers, such as the Yamaha DX7II & most synths from the 80's!

The Montage/MODX synths' Pitch Bend has an increasingly noticeable micro or mini-Stepping like quality to it the higher/lower the pitch bend is set to on both AWM2 and FM-X PARTs. And even more noticeable the slower you bend the notes vs bending them faster. It is not smooth like on most older Synths (i.e. DX7ii).

I tested pitch bend on the 'Montage' using a Single PART Performance (FM-X) set to -12/+12.

I then took one of my single Voice Performances on the DX7II and set the pitch bend to -12/+12.

It is quite noticeable when compared side by side. The DX7 is Perfectly smooth with zero detection of any mini or micro-Stepping, no matter how slow or fast I bend the pitch. The Montage just sounds like it's micro-Stepping, but the faster I bend the less noticeable...the slower I bend the more noticeable.

Also, if I set the Montage pitch bend to -3/+3, it is much smoother and harder to tell the difference between the Montage and the DX7 set to the same -3/+3 pitch bend. If on the other hand I set the Montage Pitch Bend to -24/+24, it is very noticeable as mini-Stepping or fine-Stepping, and that much more noticeable the slower the bend; however even the fastest bend at that setting is still noticeable and not smooth! (Note that any and all FM-X & AWM2 PARTs on the Montage/MODX will reproduce the same issue...)

This is definitely something that Yamaha could and should fix, as I first noticed the issue when trying different electric guitar parts that have distortion for doing solos. They don't sound as close to a whammy bar dive bomb/bend as they could, because of the fine Step-like sound to the pitch bend, especially since some of the guitars are set well below -12 and closer to -24 or lower! Smoothing the Pitch Bend out would definitely improve the 'realism' with electric guitar solos on the Montage!

I would presume that this is doable/fixable and programmable, because if I set the Portamento on that same PART to a slower setting and go between notes that are 2 to 3 octaves apart, it is perfectly 'smooth' on the Montage/MODX and doesn't have that fine Stepping-like sound to the bending between notes that Pitch Bend does...!"

Montage/MODX Pitch Bend micro Stepping-like Sound - Not 'Smooth'

but only 7 votes for solving this issue in ideascale, it confirm what i thought, not many people are involved in the quality of pitchbend espression.