ADDS Forest Trust question

I have a query about ADDS domain trusts as i cannot wrap my head around it, allow me to build a quick scenario

2 forests forestA and forestB - They are able to resolve each other via DNS and are single domain environments S2016

Trust - 1-way transitive

ForestA -Incoming trust

ForestB - outgoing trust

Question.... This means ForestA is trusted and ForestB is trusting.. Correct?

what i do not understand is this

If i have 2 DC's we will say DCa and DCb - DCa is a domain controller within Foresta and DCb is a domain controller within Forestb

When Foresta\administrator is logged into DCa i can open ADUC and browse Forestb's domain however cannot write to it

When Forestb\administrator is logged into DCb i can write to Foresta's ADDS such as creating a new user

How is this correct unless i have the whole trusted/trusting mixed up?

However the permissions are the opposite and what you would expect, Foresta cannot assign permissions like NTFS to groups from Forestb however it works in reverse so Forrestb can assign permissions to groups in Forresta

It seems the administration side is working against the grain of the trust relationship