I'm no expert on the topic but I will share my experiences from the point of perspective of - well - an Erasmus student.
It's never easy to adapt to a new system so as usual, I had some observations.
First of all, I would like to point out that because I chose to do my mobility in my second year which isn't the usual option since most of the Architecture students would opt for this decision a bit later, in their fourth or fifth year. Since I made this decision I had to take the Portuguese courses. In the beginning, the office workers were kind enough to help me chose the teachers that would speak English so I don't start with a huge disadvantage.
The professors would always address me in English from time to time but it was still a challenge to translate the tasks and documents especially in the online course sessions.
One big difference I noticed is that the school system likes to imply group works almost in any way possible which I think is great because it teaches the students to work with each other and divide our tasks. I think this is useful considering the preparation to the real world in which let's face it we will most likely work in groups as well when delivering bigger projects.
Another thing I noticed is that the teachers have that laid back Portuguese style which means they're extremely helpful and kind but they expect you to deliver some quality work, they won't give bigger grades than you would actually deserve.
So here comes the method I genuinely didn't understand why. At my home university I'm used to the Neptun system where we can get our courses, grades and so on. Occasionally the professors would send us emails regarding the works or any news regarding the class and we all from the same year are considered as a big group of people split by the teachers we're taking the class with. At the faculty of Architecture in Lisbon, the students are divided in groups from the beginning from group A to group G and they all share one email account where they receive every email, there is no sending differently. This happened to cause quite a disadvantage for me because in the beginning I didn't really know this so I couldn't ask for a pass and while quarantining I couldn't resolve to get signed in so I missed quite a few information.
So basically these are my observations up to now, I'm still very confused about the exam period but we'll eventually get through this and I'm feeling way more prepared to start my second semester here in October.