Hi, @Cubari. It was probably the time to live (TTL) values in the previous records. @coelmay had never visited the site before so his network’s resolver did not have the previous values cached. So, for him, the new records worked immediately.
Your network (probably) had the previous DNS records cached because of TTLs. So, until the TTL expired, the new records would not work for you. This is a DNS limitation - not a Netlify limitation - and there is more information here:
If there are other questions or concerns, please let us know.