12.2.3 Can you answer these questions?

12.2.3.1 Error, non fatal with ordinary compilation, fatal with latexmk

https://tex.stackexchange.com/landing/r/digest?cta=question&id=758014

Why an error which isn't fatal with ordinary compilation (pdflatex, say), is fatal with latexmk? For instance with the following MCE (say test.tex): 
\documentclass{article} 
\begin{document} 
\textb{Foo}... 
[latexmk] [compilation-error]
 

asked by Denis BitouzA~(c) https://tex.stackexchange.com/landing/r/digest?cta=user&id=18401 Score of 1

12.2.3.2 Embed custom color profile using pdfmanagement

https://tex.stackexchange.com/landing/r/digest?cta=question&id=757971

I need to embed a custom color profile into my pdf. Looking at "l3pdfmeta.pdf" I thought this may work: 
\DocumentMetadata{ 
pdfversion = 1.7, 
pdfstandard = {A-2B}, 
lang = en-US, 
% ... 
[luatex] [color-profile] [pdfmanagement]
 

asked by HerpDerpington https://tex.stackexchange.com/landing/r/digest?cta=user&id=82853 Score of 2

12.2.3.3 How to force strict flush-left alignment in align* environments inside a minipage when text notes are added?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=757998

Note: I attempted to mod the code in my OP by integrating Mr. Carlisle suggestions in the comments below. My implementation must be wrong because the render still results in the screenshot below. 
I am ... 
[macros] [amsmath] [minipage] [alignment]
 

asked by Oregon Math Tutor https://tex.stackexchange.com/landing/r/digest?cta=user&id=371678 Score of 2