I do electrical so parsing lighting is often a big issue. (Subcontractor)

One big issue Ive had is drafters use the same symbol for different things per person. One person's GFCi is another's switched receptacle. People use the specialty putlet symbol sometimes very precisely and others not. Often accompanied by an annotation (e.g. 6-15R).

Dimmers being ambiguous is huge; avoiding dimming type mismatches is basically 80% the lutron value add.