Interestingly, I was working more on the new site today and ran into another problem with my next section (container tagged as section) with inner container… leading to a similar problem and what I suspect is part of why I’m struggling so much since v1.4 was introduced, seems I may have stumbled into yet another bug… 
In my scenario, it seems that when adding Stretch to the Align-Container on a custom CSS class, it spreads everything out without respecting the content width setting. However, if I were to either remove that Stretch value on the custom CSS class and used it instead on the ID, it worked fine, even if it was on the ID and the custom Class (since the ID always overrides the custom class anyways). Effectively, I needed to use Stretch on the ID, no matter what, and it doesn’t seem to work when using a custom CSS class - basically seems completely broken when using that on a custom CSS class.
I think this is a bug and may even be related (or identical) to what was reported here too: https://forum.bricksbuilder.io/t/automatic-css-responsive-width-class-overwritten-by-the-section-stretched/3298 - “My problem (wanting to apply a width class to box the content while keeping everything responsive) is solved with the width variable being applied in “width” (and not in max-width) (but weirdly this solution works only on the ID level and doesn’t work when it’s in a custom class…)”
I recorded my screen for review / confirmation and it can be viewed here: https://filesharing.d19.ca/f.php?h=304KWbnW&p=1
I think there’s been far too many of these kinds of weird issues since v1.4, and it’s really adding to a lot of frustration trying to design with it, unfortunately. I really want to use Bricks instead of Oxygen for my current project as I’d hate to have to re-do it back in Bricks so soon afterwards, but I’m really struggling with this since v1.4. Hoping v1.4.1 comes soon with these fixes as I’ve reported a few now in v1.4. In fact I had reported similar behaviour for the 1,.4 beta but seems they may have not been taken into account before the stable release. 