Matrix from Layers error after QGIS 3.6

[davidlgalt]

I am getting aa error using Matrix From Layers that shows up sometime after QGIS 3.6. I can still use the stable release 3.4 without encountering the bug. It's a bit difficult to explain, but here goes.

When I create a model that creates an autoincrementing field and follow that with Matrix from Layers everything works, but If I try to call that model from another model, I get an error saying that it can't find auto_inc_id.

And then it got weirder. It worked when I called it from some models but not others. After lots of debugging, I discovered that models that also use the Add Autoincremental Field, even if they're completely separate branches and don't interact at all.

I'm not sure if this is an issue with QGIS or ORS.

I'm currently using QGIS 3.40, but also observed the error on 3.8.

Here are the models, test project and data:
https://ln5.sync.com/dl/daf48be60/s37quhwp-7pi2yreh-mmrc7keq-q4j9ssru

[merydian]

Hi,
thanks for your contribution here. None of the provided models produce an error on my end. Please give some more details and an error message, then we can help you out further.
You might want to try using a different user-profile, if this is a QGIS related issue.

[davidlgalt]

I created a new profile, but am getting the same error:

[merydian]

This error message suggests that the field auto_inc_id is not found in the input layer of that processing step. It doesn't seem to be present there. So this most likely isn't a problem with ORSTools, since the plugin gets that value directly from the processing algorithm source.
Any possibility of a typo between the processing step parameters? Maybe try using an input string and set the value to that in both steps.
I still can't reproduce your error with the provided project and data.