You still aren't really helping us. You were given this (we've moved on in days now):
=$L$4=TODAY()
and it highlights the whole of the day, as you have just said you want, but earlier you said that it also highlighted the second column, which you say you don't want, yet the file attached shows just that. You are going to need to manually shade the cells to show us what you want.
If you are expecting only one half of the merged cells to be highlighted, then you are on a hiding to nothing - that's never going to heppen.