Warning for old Production lines

I have build a new production line with more specialization on it while researching new features.
When added these feature the old lines give no warning that these feature are not possible to put in the car on them. So i ended with a bunch of cars with missing features i could not figure out where they come from.
On the line while selecting the cars there is no info for missing features, only for defects.
And on the sell tab you see all the missing features but there is no info which production line they came from.

If you don’t upgrade a slot the cars will stop there. For you to buy the upgrade to install the feature. But lines without the specializations just don’t install them without any warning or info.