Serialiser_Engine: Serialisation of components stopped working

[LMarkowski]

Description:

As in header. It happens with both alt and crtl+c,v copying. I'm using today's (210412) daily alpha.

Steps to reproduce:

Copy working component.

Expected behaviour:

Pasted component shouldn't be magic.

Test file(s):

SP

[pawelbaran]

@adecler this looks like a critical bug 🙈