Lego... incompatibilities?

Isn't compatibility a huge part of the draw of Lego?

I've never heard of incompatibilities, what are they?

The only problem I've noticed product wise is there are now mold defects after they started adding recycled plastic, only one or two minor (visual surface) imperfections per box, but before, there were none.

Perhaps a reference to the change of the color grey (now in time immemorial) to “bley” or bluish gray.

Tons of e-ink spilled over it and some never recovered.

Probably the bionicals... Disaster?

Lots of those pieces look like technics, but aren't.