Pretty simple application of the law here
by wcnitz (2018-12-05 14:19:30)

In reply to: Technically, it was a second yellow.  posted by NDBass


What Sterling did is a caution for a player, and as you said it was his second and he was sent off correctly.

A manager entering the field without permission isn't an explicit offense for sending off, just a violation of the constraints to remain in the technical area (which is violated routinely in every match). Basically, in most circumstances, a manager will get a verbal warning (effectively a caution) for this. The FA can then decide if it's a greater violation according to its own local regulations.