This just happened to me too, I made 1000% sure all pipes were connected properly, redid them twice and this was still happening.

I even set up a delete filter to remove just pipes (both, regular and underground) and then rebuild them all with Ctrl+Z, but the issue persisted.

At some point, I ...

When there are no materials for the bots to build something they are displayed as variables and weird names instead of the actual name

For example, when you lack a single piece it should say:

A una entidad le falta el material para la construcción

On the other hand, when you lack multiple ...