From annawiki

Zone Africa/Luanda 0:52:56 - LMT 1892
0:52:04 - AOT 1911 May 26 # Angola Time
1:00 - WAT


With the Portuguese law linked:

I'd suggest that the data should be changed from 1911 May 26 to 1
January 1912, but I don't have much Portuguese language expertise to
confirm this...

It seems to be a decree [en nome da Republica se decretou], not law, and it doesn't mention AOT nor WAT.