[LinuxCNC/linuxcnc Issue#285] Inconsistent mode switching

Here are the steps I follow to reproduce the issue:

1. Start a config (axis_mm)
2. Power on the machine
3. Switch to MDI mode

This is what I expected to happen:

halui.mode-is-mdi activates

This is what happened instead:

halui.mode.is-mdi activates for a short moment and then halui.mode.is-manual is active again.
If MDI command is executed the mode switches to MDI.

Also, the machine starts in manual mode, then switches to a different mode for a brief moment, then switches back to manual (I have a LED and a relay connected to halui.mode.is-manual so I can see and hear that).
Edit: The latter is not really confirmed. Probably the machine starts in some other mode and then switches to manual.

It worked properly before this:

Not sure about 2.7

Information about my hardware and software:

I am using Debian image.
I am running a binary I built myself from source.
I am using this LinuxCNC version v2.8.0-pre1-3169-gdf1c3ba