Opening an old scene disables the add-ons... Bug or feature?

I am not familiar with bug tracking, and I don’t know how to do it, but I’ve noticed really unexpected behavior from Blender that needs to be addressed. Please don’t tell me that i need to submit it as a bug, because it can be easily checked.

Opening an old scene disables the add-ons
Using other interaction preset than default does the same

I’ve circumvented second problem by using other interaction preset than default (in the input tab) and then Blender behaves correctly, until you hit Ctrl + N to make a new scene. After that Add-Ons are disabled again.

Is this a Bug or feature?

Other observation:

Interaction preset (other than good ol’ blender) set as default works correctly (see above)… kind of - for example selection presets that some authors had added to the key configuration (left click marquee) don’t work.

Am I the only one experiencing those problems?