I agree with the OP: When I use a password manager, the typical “API” between the password manager and the login form is (1) paste username, (2) TAB, (3) paste password, (4) ENTER.
With the intervening “Skip” link (which surprisingly appears only after I - rather, my password manager - start typing my username), this sequence is broken.
Yes, most password managers allow to change the default sequence, but this requires a manual change to an otherwise mostly universally accepted “API”. That’s a nuisave to the knowledgeable and a no-go for the novices and will results in less usage of password managers, which will ultimately reduce the overall security of using Discourse. (I am talking as a Fairphone forum user.)
From a UX perspective I see no reason why the “Skip” link must be placed into this particular position. It is a feature which is probably used rarely, when the password was forgotten. (I don’t know whether you have statistics pointing otherwise, though.)
So I would strongly advocate to keep the previous design.
Danke & Grüße von
nobi