Yes, but you could print incompatible materials before just fine. It was just either time-consuming (manual change) or time-consuming and wasteful (AMS-like systems that cut filament)
Printing multiple materials with an AMS-like system will usually cause print failures. Remnants of the materials will stick in the single print head and mix with the incompatible materials. And manually switching isn't feasible if you're trying to do something like print supports--are you going to swap filament rolls by hand every layer?
I've printed _many_ parts with multi-material using AMS: PLA, PETG, different support materials. Never had a single failure. It's wasteful, but never had issues.
> And manually switching isn't feasible if you're trying to do something like print supports--are you going to swap filament rolls by hand every layer?
No, first because I would use support material just for the interface and if it's curved, then no. Even with X1C's AMS, any IDEX, H2D print time would be hilariously ballooned. I'n saying that dual-nozzle design didn't make it possible, it made it more convenient.
That is curious. I've only tried multimaterial work with an AMS Lite on an A1, but it critically compromised layer bonding due to residue, and it was a reproducible problem.
I've printed both PETG and PLA just fine (using PETG as a support interface) in the AMS. The key is to turn off the prime tower, and increase the flushing volume between those materials. (I do now have an H2D, and it's definitely an upgrade over having to do that)
Two heads lets you keep them completely separate which is good because PETG to PLA tends to jam and you need to purge a LOT to get all the PETG out or it can mix with the PLA causing really weak parts.