Onno

Hi Ron,
 
Thanks for flagging this! UltiMaker firmware developer here: I've been looking into this issue today.
 
Could it be that this happened during a dual-material print?
 
From testing I've been doing today, it looks like automatic material switch-over works as expected in a single-material print. However, as soon as I try the same thing in a dual-material print, the printer hangs forever during the switching process. If this is the same thing you've been seeing, then this indeed appears to be a rather unfortunate regression in 8.3.0. I'm very sorry about that! Downgrading to current stable (8.2) should for now solve the issue.
 
If there are any additional details you could provide us, those would be very welcome. What kind of print configuration did this happen in? (Number of materials in the print, single- or dual-material print; etc.) And what are the exact symptoms you're seeing? Especially knowing what you see on the touchscreen when this happens, would be helpful.
 
Best regards,
 
 
Onno

Hi Walter,
 
Thanks for bringing this to our attention.
 
I can confirm that the behavior of the /print_job/state REST API endpoint has regressed with our 8.x firmware release. My apologies for the inconvenience this must have caused!
 
I've just pushed a fix for this to our internal systems, but I can't make any promises as to public availability of this fix yet. I'll keep you posted if I can share more.
 
For now, I can also confirm that the problem appears to be submitting a request to pause the printer, while the printer is currently executing a "resume from pause" command. If you would be able to add a check for that to your script, that should provide you with a workaround. (As far as I can see, asking the printer to pause while it's currently resuming, previously just caused your request to be ignored by the printer. The ER999 you get now is the regression. So adding the check would probably be a good idea anyway.)